We recently moved a client from MS Exchange Email to Office365, all accounts and profiles have been created in Outlook and mail flow is fine.
When users open Outlook, they receive a security alert with the error "The name of the security certificate is invalid or does not match the name of the site". Users can proceed and are prompted once more, again proceeding, they then receive a prompt for user credentials to connect to the old remote Exchange server, this can also be skipped by without causing any issues sending/receiving mail.
How can the messages be prevented from appearing when opening Outlook ? So far we have tried disabling all MS Exchange services on their Windows SBS server and flushing DNS cache locally. I have also attached screenshots.
Many Thanks in Advance