I'm still trying to install Thunderbird with a MSO365 email essentials account. I'd prefer POP3, but have tried IMAP and Exchange/MS365. Regardless of configuration type, I'm getting nowhere... The error message says: 'Configuration could not be verified. If your username and password are correct, it's likely that the server administrator has disabled the selected configuration for your account. Try selecting another protocol.' I've tried all three, and as many variations of username as I can think of (the form says "Your full name", only the error message says username). Please help me to get an account setup, so I can begin using Thunderbird. Victoria.