This seems to be caused by Adguard HTTPS filtering. Disabling Adguard should allow Mailbird SMTP STARTTLS connections to complete without issue and the emails to send properly.
Articles in this section
- Mailbird freezes or hangs
- I cannot send/receive emails anymore
- I am unable to add my email account in Mailbird/ "Authentication failed" message
- I can't receive or send email anymore
- Problem installing or setting up
- Having trouble sending E-mails?
- I am unable to install Mailbird
- Cannot activate license (Cannot connect to server/only show pink colour)
- Error sending mail from AOL
- My emails get deleted or marked as read automatically in Mailbird