Hi Folks, I have been a Thunderbird user for the past 15 years, it's perfect for managing my array of email accounts. Two days ago at around 3.00pm UK time, it suddenly stopped downloading emails from the company Office 365 server, although I can still send emails. All other email accounts, including another 365 based account are working just fine. The company IT manager has said that he can find nothing that has changed, so as a temporary fix, I set up email forwarding to one of my other accounts, but I have been informed that any emails now sent to the company email address just gets bounced back??? I have re-booted both TB and the HP laptop, updated TB, update Avast, deleted and re-established the account, all to no avail. Any ideas most welcome. Thanks, David.