Oleksandrs Vozņenko

@glajarige Thank you for the reference. I reviewed the documentation section. However, the documented workaround appears to be related to Gmail and suggests changing the encryption setting from tls to ssl. In our case the provider is Microsoft 365 SMTP OAuth, using smtp.office365.com on port 587. According to Microsoft, port 587 is expected to use STARTTLS, not implicit SSL. Therefore, when iTop builds the connection as ssl://smtp.office365.com:587, the TLS negotiation fails with “wrong version number”,...

@glajarige Thank you for the reference. I reviewed the documentation section. However, the documented workaround appears to be related to Gmail and suggests changing the encryption setting from tls to ssl. In our case the provider is Microsoft 365 SMTP OAuth, using smtp.office365.com on port 587. According to Microsoft, port 587 is expected to use STARTTLS, not implicit SSL. Therefore, when iTop builds the connection as ssl://smtp.office365.com:587, the TLS negotiation fails with “wrong version number”,...

Dear Uchiyama, During testing after upgrading from iTop 3.2.2 to 3.2.3-1, a potential issue was identified with Microsoft 365 SMTP OAuth when TLS encryption is configured. With the following setting: 'email_transport_smtp.encryption' => 'tls' the connection appears to be established using SSL (ssl://smtp.office365.com:587) instead of STARTTLS on port 587, resulting in the error below: Connection could not be established with host "ssl://smtp.office365.com:587": SSL operation failed with code 1. OpenSSL...