Authentication error due to self-signed SSL certificate

I use ProtonMail email service, which is a secure email provider. Due to the security design, their servers do not directly allow SMPT/IMAP connections. Instead, they created an application called “Bridge” which installs on a local user computer, connects to the mail server, and acts as an SMTP and IMAP server to which mail clients are then able to connect.

When I set up SMPT parameters as per Bridge instructions, Manager gives me an error “The remote certificate is invalid according to the validation procedure.” This happens because Bridge provides a self-signed SSL certificate, which is perfectly fine for a local setup. Unfortunately, it’s not possible to “ignore” that the certificate is self-signed and not trusted in Manager. Does anyone have any solutions to such set-up? It would be nice if developers could allow to connect to an SMTP server that uses self-signed SSL certificates, with a warning to user.