Lookup for "250 5.7.2"
Permanent Error - This status code indicates a permanent issue and is unlikely to resolve itself. You should contact the Email Service Provider.
Basic Status Code Details (250)
Requested mail action okay, completed
Enhanced Status Code Details (5.7.2)
Mailing list expansion prohibited
The sender is not authorized to send a message to the intended mailing list. This is useful only as a permanent error.