We were having this issue with one of our employees. He would login using his network password. He could access our Outlook Web App (OWA) which requires his same network password; however, when we entered that password into his Outlook we would get “Wrong username or password“.
The solution came with the “Credential Manager“. There was a long “MicrosoftOffice15_Data:orgid:….“. I click on this to expand and hit “Remove from vault“, and this fixed the issue.
Although this worked for several customers we had one that required us to create a new profile in the Mail portion of the Control Panel.
Let us know if this helped you…