After I updated Matomo, it stopped working (blank page, widgets not loading, error message, etc.). How can I fix this?

When you upgrade Matomo to the latest version, it sometimes happen that Matomo stops working – especially when the User Interface is not working (blank white page, widgets not loading, error message, etc.).

Work through the following troubleshooting steps in order. After each step, refresh the Matomo page and check whether the issue is resolved. If the problem persists, continue to the next step.

1. Delete your browser cache or try to access your Matomo with a different browser.
2. Delete all files in matomo/tmp/. After deleting the files and directories, refresh the page.
3. Activate the display of PHP errors in your web server configuration. This may provide a useful error message page.
4. Check your web server error logs. Look for Matomo-related errors that may explain why the interface is not loading.
5. Reupload all Matomo files from the latest version. Sometimes files are not uploaded correctly during an upgrade, leaving your installation in an inconsistent state. Upload all files again and verify that the upload completed successfully.
6. Temporarily disable any CDN, caching, or performance plugins. For example, this may include WordPress performance plugins or other website optimisation tools. Disable them temporarily to determine whether they are preventing the Matomo interface or its assets from loading correctly.

If the issue persists, review the troubleshooting guides for updating On-Premise or Matomo for WordPress, as they may describe a solution for your specific problem. If you still cannot resolve the issue, search the Matomo Forums and the Matomo Knowledge Base.