If group messages sent to your email address are returned to Yahoo! Groups as undeliverable ("bouncing"), your Yahoo! Groups account may be temporarily disabled.
Messages can be returned for several reasons:
In many cases, Yahoo! Groups can automatically reactivate your account once the delivery problem is solved. However, this process can sometimes take a few days. To immediately reactivate your account:
Note: Reactivating your account will NOT immediately restore email delivery. The change in your status still needs to be propagated to all your groups. Usually, this happens within hours, but there may be occasions (particularly if you’re in a group with more than 75 members) when it may take a day or more.