[Mailer] SMTP Authentication is not performed when using STARTTLS. #34522
Description
Symfony version(s) affected: 4.4.0, 5.0.0
Description
Capabilities reported in EHLO after performing STARTTLS are ignored. It's possible that the AUTH-capabilitiy is only reported after the STARTTLS-command. In such situations the communication with the smtp-server would be unauthenticated, and the sending of emails would fail (in most situations).
How to reproduce
Use the mailer with an smpt-server (like postfix) using submission and STARTTLS.
Possible Solution
Move $capabilities = $this->getCapabilities($response); after the block which starts STARTTLS and use the response from the second EHLO-command, like it was in 4.3.
Additional context