Please open Mailwasher Pro and click, Settings>>Accounts, click your account and click, "Remove Account", click, "Yes, remove it", close and restart Mailwasher Pro.
In Mailwasher Pro click, Settings>>Accounts "Import Account" and follow the directions.
If there are no amounts listed, cancel to exit this screen and click, Add Account, choose your account type and add account manually.
Full directions are available for this from here:
Mailwasher Pro >> Help >> Help Topics >> Settings Screen >> Accounts
Please let me know how you get on there.