If your GitHub Pages code contains an unrecognized Liquid tag, your GitHub Pages site will not build.
If your GitHub Pages site fails to build because of an unrecognized Liquid tag, you'll get an email that looks like this:
Subject: Page build failed
The page build failed with the following error:
The tag `fake_tag` in `index.html` is not a recognized Liquid tag.
Troubleshooting unrecognized tag errors
Tip: We strongly recommend running Jekyll locally so you can easily debug and fix build errors before pushing to GitHub. To learn more about troubleshooting options, see "Troubleshooting GitHub Pages builds."
- Check the tags in the referenced file. They should match those in Jekyll's default variables. Make sure there are no typos in your tag names.
Check plugin output for unrecognized tags
Plugins are a common source of unrecognized tags. Since GitHub doesn't support most plugins, a common workaround is to build locally and include the results in the Pages repository. However, sometimes this workaround includes tags that are not in Jekyll's default variables, which the build cannot parse. For a list of supported plugins, see "Adding Jekyll plugins to a GitHub Pages site."
Once you've fixed any tag errors, you will need to commit your changes and push to your GitHub Pages repository again to trigger another build on the server.