XF 2.1 Error on mailing

[Nicky Vermeersch]

I've been using a Gmail account since a few years to send the registration and notification emails to the members. Since a few days ago, I noticed there were 4000 pages of errors all in regard to an error I can't wrap my head around:

Server error log
 
     
         
[LIST]
[*]             
[*]Swift_TransportException: Email to someuser@gmail.com failed: Expected response code 250 but got code "", with message ""
[*]            
[*]src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php:383
[*]         
[/LIST]
        
[LIST]
[*]             
[*]Generated by: Unknown account
[*]            
[*]Jun 10, 2020 at 4:03 PM
[*]         
[/LIST]
     
       [SIZE=5][B]Stack trace[/B][/SIZE]
           #0 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(281): Swift_Transport_AbstractSmtpTransport->_assertResponseCode('', Array)
#1 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/EsmtpTransport.php(270): Swift_Transport_AbstractSmtpTransport->executeCommand('RSET
', Array, Array)
#2 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/Esmtp/Auth/LoginAuthenticator.php(46): Swift_Transport_EsmtpTransport->executeCommand('RSET
', Array)
#3 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/Esmtp/AuthHandler.php(176): Swift_Transport_Esmtp_Auth_LoginAuthenticator->authenticate(Object(Swift_SmtpTransport), 'username@g...', '*****')
#4 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/EsmtpTransport.php(332): Swift_Transport_Esmtp_AuthHandler->afterEhlo(Object(Swift_SmtpTransport))
#5 src/vendor/swiftmailer/swiftmailer/lib/classes/Swift/Transport/AbstractSmtpTransport.php(118): Swift_Transport_EsmtpTransport->_doHeloCommand()
#6 src/XF/Mail/Mailer.php(274): Swift_Transport_AbstractSmtpTransport->start()
#7 src/XF/Mail/Queue.php(138): XF\Mail\Mailer->send(Object(Swift_Message), Object(Swift_SmtpTransport), Array)
#8 src/XF/Job/MailQueue.php(12): XF\Mail\Queue->run(G)
#9 src/XF/Job/Manager.php(253): XF\Job\MailQueue->run(G)
#10 src/XF/Job/Manager.php(195): XF\Job\Manager->runJobInternal(Array, G)
#11 src/XF/Job/Manager.php(79): XF\Job\Manager->runJobEntry(Array, G)
#12 job.php(42): XF\Job\Manager->runQueue(false, 8)
#13 {main}
    
       [SIZE=5][B]Request state[/B][/SIZE]
           array(4) {
["url"] => string(18) "/community/job.php"
["referrer"] => string(78) "https://www.mcmiddleearth.com/community/threads/5961/"
["_GET"] => array(0) {
}
["_POST"] => array(0) {
}
}

I've checked and the password did not change, nor did the settings for the SMTP server. I've also tried adding an 'App password' with Google and use that to avoid any problems with 2FA that might happen during the authentication, but this did not work either.

When I searched for what the error 250 means for SMTP, it is 'Failed Authentication'. I'm pretty clueless as I tried using the 'normal' password for Gmail and the 'App' password, and neither of them works :\

 

[Nicky Vermeersch]

It seems the issue returned, I assumed it worked since the errors were not appearing anymore.

I tried reinstalling Sendmail but that didnt work, and I also tried Postfix, but I keep getting errors 'Unable to send mail'.

edit: It also looks like there are only 2 users who are generating a massive amount of errors. I just tried sending a test from the 'Communication' panel to my own private email, and it works.

Could it be that the "Mailqueue" or something has stuck jobs?