I use CiviCRM (v5.20.0 on PHP 7.3.11 in Joomla) to send scheduled reminders for membership expiration. The mails are sent via SMTP. This works okay when i send a reminder to my own account so i expect it to work for all other accounts. Though I would like to see if mails are indeed sent but I don't see any logging where i could find if, when and to whom an e-mail has been sent.

Now I found an extension called Transactional Mail - Bounce and Tracking Handler and i installed it. When i try to send mail via the Job Send Scheduled Reminders, I see following error (only when the extension is enabled):

Failed to set sender: b.1.49.90b5f37ff0be023e@ [SMTP: Invalid response code received from SMTP server while sending email. This is often caused by a misconfiguration in Outbound Email settings. Please verify the settings at Administer CiviCRM >> Global Settings >> Outbound Email (SMTP). (code: 501, response: : domain missing or malformed)]

Any help would be appreciated.

2 Answers 2


The invalid sender address in the messages suggests that you have not set up your CiviMail -> Mail Accounts bounce account with a proper domain - that sender would normally have that domain after the @ sign.


Thanks for the answer. I was testing with my own mailaccount in Civimail. When I changed the setting to Used for Bounce processing, i lost all my emails in the inbox although the account was setup as IMAP. I was lucky to have a backup :) I found out how to track to whom a reminder has been sent (Reports>Contact reports>Activity Summary). For me this also is okay so far.

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