Occasionally Yahoo finds that a message from the egroup is 'bounced' back (i.e. the message is undeliverable) because, say, the recipient's mailbox is full, the recipient's ISP has a backlog of email to process, or a spam checker prevented it getting through, or some other reason.
Some of these are reasons the intended recipient could not know about (such as an ISP backlog) and some the recipient might know (e.g. closing down the email address without changing it on the Yahoo website or informing the ICG egroup moderator!)
There are 'soft bounces' and 'hard bounces'.
Soft bouncing
A 'soft' bounce is a 'temporary delivery failure', such as an overfull mailbox. Yahoo will accept that the bounced message couldn't be delivered but will attempt to deliver future messages, and if the original problem has been resolved (e.g. a person's full mailbox has been cleared, or the ISP has caught up with its backlog of emails) the recipient sees the later message but not the earlier bounced one.
Occasionally this can mean that a member sees replies to an earlier post without having seen the original post (i.e. if the original post bounced).
Hard bouncing
A 'hard bounce' is a 'permanent delivery error'. This is rare but generates messages (which the moderator can look up) such as:
- "Mailbox would exceed maximum allowed storage"
- "This account has been disabled or discontinued" (the member needed to tell the moderator about this)
- "Unknown name"
- or the impenetrable "The following address had permanent fatal errors"
Yahoo suspends sending egroup messages to the affected email address, which it regards as de-activated, and instead sends a series of test messages to the individual to reactivate the account by clicking on a button. If a test message gets through, it means the problem has solved itself somehow, and the member can click on the button to tell Yahoo's computer, which puts the email address back onto its active list and normal service is resumed. Yahoo will also reactivate the account if a test message is not returned as undeliverable after five days.
The moderator can go to the Yahoo website and see who (if anyone) is currently being 'bounced', and can then send an activation message if necessary.
Where does the problem lie?
In general, bouncing arises because of problems at the ISP or the recipient. It is not generally a fault with Yahoo or the egroup, though occasionally it might be (e.g. if an email address gets corrupted in Yahoo's computers, which is known to have happened in one case).
Reading missed messages on the archive
As far as missed messages are concerned, egroup members who are fully signed up to Yahoo with their own password and ID can always go onto the Yahoo website to look up any messages that have been missed - though of course that's not the ultimate solution because members want all messages to arrive automatically.