Docs header transparent bg

How to troubleshoot RubyGems and Bundler TLS/SSL Issues

If you’ve experienced issues related to SSL certificates and/or TLS versions, you’ve come to the right place. In this guide, we’ll explain how both of those issues come about and how to solve them. Many of the instructions in this guide can help fix either the SSL certs issue or the TLS version issue.

If you’re not interested in the reasons, and just want to get things fixed as quickly as possible, you can jump straight to solutions for SSL issues.

Table of Contents

The Problems

Why am I seeing certificate verify failed?

If you’ve seen the following SSL error when trying to pull updates from RubyGems: OpenSSL::SSL::SSLError: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

This error happens when your computer is missing a file that it needs to verify that the server behind is the correct one.

The latest version of RubyGems should fix this problem, so we recommend updating to the current version. To tell RubyGems to update itself to the latest version, run gem update --system. If that doesn’t work, try the manual update process below.

(What do we mean by updating “should fix this problem”? Review the What are these certificates? and How Ruby uses CA certificates sections below to gain a better understanding of the underlying problems.)

What are these certificates?

Anytime your computer is talking to a server using HTTPS, it uses an SSL certificate as part of that connection. The certificate allows your computer to know that it is talking to the real server for a domain, and allows it to make sure that your computer and that server can communicate completely privately, without any other computer knowing what is sent back and forth.

To know if the certificate for is correct, your computer consults another certificate from a Certificate Authority (CA). The CA certificate bundle includes certificates from every company that provides SSL certificates for servers, like Verisign, Globalsign, and many others.

Each CA has a “root” certificate that they use to verify other certificates. The CA certificates are called “root” because they sign other certificates that sign yet other certificates, and a graph of the certificates would look like a tree, with the “root” certificates at the root of the tree. Your computer will use its built-in CA bundle of many root certificates to know whether to trust an SSL certificate provided by a particular website, such as

Occasionally, new companies are added to the CA bundle, or existing companies have their certificates expire and need to distribute new ones. For most websites, this isn’t a huge problem, because web browsers regularly update their CA bundle as part of general browser updates.

How Ruby uses CA certificates

The SSL certificate used by descends from a new-ish root certificate. Ruby (and therefore RubyGems and Bundler) does not have a regularly updated CA bundle to use when contacting websites. Usually, Ruby uses a CA bundle provided by the operating system (OS). On older OSes, this CA bundle can be really old—as in a decade old. Since a CA bundle that old can’t verify the (new-ish) certificate for, you might see the error in question: certificate verify failed.

Further complicating things, an otherwise unrelated change 18-24 months ago lead to a new SSL certificate being issued for This meant the “root” certificate that needed to verify connections changed. So even if you’d previously upgraded RubyGems/Bundler in order to fix the SSL problem, you would need to upgrade again—this time to an even newer version with even newer certificates.

Troubleshooting certificate errors

Start by running the automatic SSL check, and follow the instructions. You might need to update Bundler, update RubyGems, manually update RubyGems certificates, or perhaps even install new OS certificates.

Why am I seeing read server hello A?

This error means that your machine was unable to establish a secure connection to The most common cause for that problem is a Ruby that uses an old version of OpenSSL. OpenSSL 1.0.1, released March 12, 2012, is the minimum version required to connect to, starting January 1, 2018.

To understand why that version is required, keep reading. To see instructions on how to update OpenSSL and/or Ruby to fix the problem, skip to the troubleshooting section.

SSL and TLS protocol versions

Secure connections on the internet use HTTPS, the secure version of HTTP. That security was originally provided by SSL, an acronym for Secure Sockets Layer. Over time, researchers discovered flaws in SSL, and network developers responded with changes and fixes. After SSL 3.0, it was replaced by TLS, or Transport Layer Security.

Over time, TLS was also revised. TLS version 1.2, originally defined in 2011, and supported by OpenSSL starting in 2012, is the current standard. In 2017, every version of SSL and TLS older than TLS 1.2 has been found to have critical flaws that can be exploited by a determined or knowledable adversary. As a result, security best practices suggest actively blocking all versions of SSL, as well as TLS versions 1.0 and 1.1.

TLS 1.0 and 1.1 are deprecated uses a 3rd party CDN provider called Fastly, which lets users all around the world download gems really quickly.

Last year, Fastly announced it will deprecate TLS versions 1.0 and 1.1 due to a mandate published by the PCI Security Standard Council. (Read more about this in Fastly’s blog post.)

As a result, will require TLSv1.2 at minimum starting January 2018. This means and the gem command will no longer support versions of Ruby and OpenSSL that are do not have support of TLS 1.2.

Troubleshooting protocol errors

To troubleshoot protocol connection errors, start by running the automatic SSL check, and follow the instructions. You might need to update Bundler, update RubyGems, or even reinstall Ruby (you can find reinstallation instructions by version manager or package manager.)

The Solutions

Automated SSL check

First, run this script to check whether your errors result from the SSL certs issue or the TLS versions issue.

You can run the script immediately with this command (Windows 10 also):

$ curl -Lks '' | ruby

If the output reads “Your Ruby can’t connect to because you are missing the certificate” you have a certificate verification error, and need to update your certs.

If you instead see “Your Ruby can’t connect to because your version of OpenSSL is too old” your OpenSSL version is old and incompatible with TLSv1.2, and you need to upgrade your OpenSSL and/or recompile Ruby to use a newer version of SSL.

The instructions in this guide can help you troubleshoot both problems.

Updating Bundler

Update to the latest version of Bundler by running:

gem install bundler

Updating RubyGems

You might be able to upgrade RubyGems using the self-update command:

gem update --system

If that command fails, you can try downloading the latest RubyGems yourself and installing it, using these steps. In this example, we will be downloading and installing RubyGems 2.7.6. If the latest version of RubyGems has changed by the time you are reading this, you will need to change anyplace you see 2.7.6 to the version of RubyGems that you have downloaded.

  1. Using your web browser, head to the Download RubyGems page, and download the gem version of the latest rubygems.
  2. Once you’ve downloaded the gem, open on macOS, or Command Prompt with Ruby on Windows.
  3. Change directories to your Downloads folder. On macOS, the command would be cd ~/Downloads. On Windows, it would be cd C:\Users\%USERNAME%\Downloads.
  4. Install the downloaded RubyGems upgrade gem by running gem install --local rubygems-update-2.7.6.gem.
  5. Run the upgrade command update_rubygems.

You’re done! Run gem --version to verify that you are using the latest version of RubyGems.

Updating System Clock

If your system clock is set to a time in the past or future, your machine will not be able to establish a secure connection to To resolve the issue, you will need to set your system clock to the current time. In Linux, you can update the system clock by running sudo ntpdate

Here are other possible solutions for updating a system clock:

Updating CA certificates

Installing new RubyGems certificates

If you’re unable to update RubyGems, you can manually add the certificate RubyGems needs. If you have a version of RubyGems new enough (version 2.1.x and above) that can use those “vendored” certificates—and you install the certificate successfully—it will work without upgrading the RubyGems version.

Warning: These instructions will only add new certs; Ruby will be left untouched. To ensure your Ruby version can use TLSv1.2, run the snippet again. If not, follow a different set of instructions in this guide for upgrading Ruby as well.

Step 1: Get the new trust certificate

Download the .pem file from this link: GlobalSignRootCA.pem

Then, find the downloaded file, and check to make sure the filename ends in .pem. (Note: Some browsers will change the extension to .txt, which will prevent this from working. So it’s important to make sure the file you downloaded ends in a .pem extension.)

Step 2: Locate RubyGems certificate directory in your installation

Next, you’ll want to find the directory where you installed Ruby in order to add the .pem file there.

On Windows:

Open your command line and type in:

C:\>gem which rubygems

You’ll see output like this:


To open a window showing the directory we need to find, enter the path part up to the file extension in the same window (but using backslashes instead). For example, based on the output above, you would run this command:

C:\>start C:\Ruby21\lib\ruby\2.1.0\rubygems

This will open an Explorer window, showing the directory RubyGems is installed into.

On macOS:

Open Terminal and run this command:

$ gem which rubygems

You’ll see output like this:


To open a window showing the directory we need to find, use the open command on that output without the “.rb” on the end, like this:

$ open /opt/rubies/2.4.1/lib/ruby/2.4.0/rubygems

A Finder window will open showing the directory that RubyGems is installed into.

Step 3: Copy new trust certificate

In the window, open the ssl_certs directory. Find other .pem files like AddTrustExternalCARoot.pem (may be located in subdirectories like and drag your file beside them.

Once you’ve done this, it should be possible to follow the directions at the very top to automatically update RubyGems. Visit the Update RubyGems section for step-by-step instructions. If that doesn’t work, keep following this guide.

Installing new OS certificates

This solution might work when the version of OpenSSL installed with Homebrew interferes with Ruby’s ability to find the correct certificates. Sometimes, uninstalling everything and starting again from scratch is enough to fix things.

First, you’ll want to remove RVM. You can do that by running this command:

$ rvm implode

Next, you’ll want to remove OpenSSL from Homebrew. (Using --force ensures that you remove all versions of OpenSSL you might have):

$ brew uninstall openssl --force

Now, you can reinstall RVM, following the instructions from the previous step.

Reinstalling Ruby from version managers

Installed with rvm

Note: Try this solution if updating SSL certificates with RVM doesn’t work. If Ruby installed with RVM can’t find the correct certificates even after they have been updated, you might be able to fix it by reinstalling RVM and then reinstalling your Ruby version.

Run these commands to remove RVM and reinstall it:

$ rvm implode $ \curl -sSL | bash -s stable

Then, reinstall Ruby while telling RVM that you don’t want to use precompiled binaries. (Unfortunately, this will take longer, but it will hopefully fix the SSL problem.)

This command will install Ruby 2.2.3. Adjust the command to install the version(s) of Ruby that you need:

$ rvm install 2.2.3 --disable-binary

Installed with ruby-build or rbenv install

Follow the instructions outlined in the Updating and Troubleshooting ruby-build guide by rbenv.

Reinstalling Ruby from OS package managers

macOS: Built-in Ruby

macOS 10.13 High Sierra comes with default Ruby that is compatible with TLSv1.2.

To check your current macOS version, go to the Apple menu and choose “About This Mac”. If you see anything other than “macOS High Sierra”, you will need to upgrade to the newest macOS (or else install a newer version of Ruby with Homebrew by following the next set of instructions after these).

To upgrade to High Sierra:

    1. Open the App Store application
    1. Choose the “Updates” tab
    1. Click the “Install” button for “macOS High Sierra”

macOS: Installed with Homebrew

Note: To install a newer version of Ruby with Homebrew, first make sure Homebrew is installed. If the brew command is not present, follow the installation instructions at and then come back to these steps.

    1. Run brew update
    1. Run brew install ruby
    1. If Ruby is already installed, run brew upgrade ruby to upgrade to the latest version.

Debian or Ubuntu 16.04: Installed with apt-get

Note: To remove Ruby with apt, you’ll need to check which versions of Ruby you have installed. apt installs Ruby v2.3.1.

To uninstall, follow the directions listed here. (These instructions work for both Ubuntu and Debian.)

Once you’ve successfully uninstalled Ruby, reinstall it by running:

$ sudo apt-get install ruby

Fedora: Installed with dnf

Note: The newest versions of Fedora use dnf as its package manager, but older versions use yum instead. If you see the error message dnf: command not found, replace the dnf in these instructions with yum.

First, uninstall Ruby by running:

$ dnf remove ruby

And then reinstall (this command will install Ruby 2.3):

$ dnf install ruby

RHEL or CentOS: Installed with yum

Follow these directions for upgrading Ruby on CentOS. (They also include instructions for troubleshooting OpenSSL.)

Windows: Installed with Ruby Installer

From the Control Panel, find the Ruby installer in “Programs”. Click on the folder, and click again on “Uninstall Ruby”. Reinstall by downloading Ruby and the Ruby DevKit at RubyInstaller.

Additional Help

Running another automated SSL check

Rerun the automated SSL check to verify if the issue lies with an SSL issue or a TLS issue. If you’ve already followed the troubleshooting steps above and are still encountering an issue, go to the creating an issue section below for next steps.

Creating an issue

If none of these instructions fixed the problem, the next step is to open an issue.

(Create an issue in the RubyGems issue tracker if your error came from gem install. If it came from bundle install, create an issue in the Bundler issue tracker.)

Please include:

  • The output from running gem env:
  • The output from running bundle env:
  • Output from running ruby -ropenssl -e 'puts OpenSSL::OPENSSL_LIBRARY_VERSION':
  • Your Ruby version manager (if any):
  • Your OS and OS version:
  • Your package manager name and version (if applicable):

Contributing to this guide

If you found a solution not listed here, submit a PR to add your solution to this guide!

Edit this document on GitHub if you caught an error or noticed something was missing.