Change user

Hi!
how can I Cange the user installed for this plugin in a sit I must modify? 
i can see this is the message:

Errors:
2021-10-25 08:49:46: Error occurred while API key validating. Error: Testing is failed. Please check the Access key.

I believe that the original user user are no longer active.
Do I have to reinstall everything again or I can just change the login credentials, because I can't find the path to do it.