Hello, We've had an issue with our Thunderbird Account, we have had to change our server settings and outgoing server from 123-reg to outlook.office365. May be easy if I bullet point what we have done.. 1. Uninstalled Thunderbird and reinstalled 2. Both server settings have been changed with the correct port and server security (123-reg have confirmed settings are correct) 3. Made sure these changes were saved 4. Closed emails and reopened 3. Receiving emails are working correctly 4. Sending outgoing emails is not working still - a pop up appears asking us to enter a password linked to smtp.123-reg.co.uk (after being changed to outlook.office) How do we make these changes stick? Foot note: passwords are correct as we have been able to log into Outlook Mail via our browser. Many thanks for taking the time to read our query. Hopefully we can find a resolution! Kind regards, Abi