Problem:

Taxonomy URLs lead to 404 page.

Solution:

The problem was not related to Toolset, but here is how to troubleshoot:

- IMPORTANT STEP! Create a backup of your website.
- Switch to the default theme such as "TwentyTwenty" by going to "WordPress Dashboard > Appearance > themes".
- Go to "WordPress Dashboard > Plugins" and deactivate all plugins except Toolset and Toolset add-ons.
- Check if you can still recreate the issue.
- If not, re-activate your plugins one by one and check the issue each time to find out the plugin that causes the problem.