I want to configure Gmail (using their "Send mail as:" feature) to send mails through my business Office365 Outlook account, , but when I try to connect it I get anAuthentication failedmessage from the Office 365 server with an error message like this:
Authentication failed. Please check your username/password. Server returned error: "334 VXNlcm5hbWU6 334 UGFzc3dvcmQ6 535 5.7.3 Authentication unsuccessful [SN6PR01CA0011.prod.exchangelabs.com] , code: 535"
I can sign in to Outlook Web App without problems using the same credentials.