LISTSERV utilizes a couple of processes in the software to remove bad addresses from lists automatically. One of these sends 'Subscription probe' emails to addresses that have resulted in errors the last time a list posting was sent to them. These emails instruct the recipient not to reply to them and have hidden content which assists LISTSERV in determining what to do if the message gets returned or rejected.
LISTSERV sends emails to the list owner(s) when errors occur informing them which addresses have had delivery errors and informing them that it is monitoring for potential removal.
If you receive one of these emails as a list owner, you should verify whether the address(es) listed are correct and update them if needed. If the address is indeed correct, no further action should be necessary and you should monitor subsequent messages to make sure the count in the Err column does not increase. If the error message contains RecipientNotFound, the address is not valid. LISTSERV monitors an address for 5 days (and continues to send you messages in that regard) unless too many delivery errors occur in the meantime in which case, it will automatically remove the bad address and inform the list owner of that action.
Example:
The following address is currently being monitored: (Remember, some
addresses may not be subscribers.)
Err First Last Address
--- ----- ----- -------
2 01/25 01/26 FREDDY.FALCON@MY.UWRF.EDU
Last error: 5.1.10 550 5.1.10 RESOLVER.ADR.RecipientNotFound;
Recipient not found by SMTP address lookup
Err= Number of delivery errors received thus far
First= Date first delivery error was received (mm/dd)
Last= Date of most current delivery error (mm/dd)
Subscribers will be automatically deleted from the list when delivery
errors have been reported for a period of 4 days or more, or when more
than 100 delivery errors have been received, whichever occurs first.
Monitoring will cease after 5 days without any reported errors.
Note: Manually deleted subscribers may remain on the monitoring report
under an alias address. Such entries will expire eventually. You do not
need to do anything about them.