Smtp details which we use are correct, for host smtp.office365.com mail is not sent every time.
Sometimes this error is generated, Fatal error: Uncaught Swift_TransportException: Failed to authenticate on SMTP server with username "XXX" using 2 possible authenticators in vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/Esmtp/AuthHandler.php on line 181
Observed behaviour
Sometimes with the same details, emails are sent.
Expected behaviour
It should send an email every time.
Can anyone please tell me what should I do?