As we know when we open PS every new day it will ask for the credential to sync, but by any chance, If the internet is disconnected and we try to open PS it removes the previously entered URL and replaces that with localhost URL and that field is non-editable.
If you are not able to edit the AE-URL/Username from the process-studio login window then you can apply the below solution to resolve this issue.
Screenshot for reference-
Took a backup of “.regconf” file from \conf folder.
Remove this file from \conf folder.
Launch the process-studio, set the correct url, username and password and click on connect. It will throw an error.
Then paste the old “.regconf” file to the \conf folder and restart the PS. It will resolve your issue.