Hi there, I've just recently started to get error messages using Thunderbird. I've made no changes and it seems to be intermittent. Error message; An error occurred while sending mail: Unable to establish a secure link with Outgoing server (SMTP) smtp-mail.outlook.com using STARTTLS since it doesn't advertise that feature. Switch off STARTTLS for that server or contact your service provider.' Receiving email seems to be OK. Any advice welcomed! Dave