Why this happens

PHP does not allow the same function or class to be defined twice in the same request. This typically happens when a plugin's files get duplicated (for example, two folders for the same plugin), or when custom code copied into functions.php duplicates a function that's already defined elsewhere.

Step-by-step fix

  1. Check the error message for the file path where the issue is.
  2. Go to that plugin's folder using File Manager.
  3. Look for a duplicate copy (e.g. both plugin-name and plugin-name-2).
  4. Delete or rename the incorrect duplicate.
  5. If the whole plugin seems to be the problem, uninstall it completely and do a fresh install.

How to prevent it happening again