To fix this problem, you need to go into ProtonMail Bridge’s advanced settings, and modify its SMTP settings to use the STARTTLS protocol, instead of its default of SSL. Please see my post in this thread for details.
To fix this problem, you need to go into ProtonMail Bridge’s advanced settings, and modify its SMTP settings to use the STARTTLS protocol, instead of its default of SSL. Please see my post in this thread for details.