Lookup for "502 2.4.7"
This status code indicates a successful delivery or other operation. Any details are simply notes.
Basic Status Code Details (502)
Command not implemented
Enhanced Status Code Details (2.4.7)
Delivery time expired
The message was considered too old by the rejecting system, either because it remained on that host too long or because the time-to-live value specified by the sender of the message was exceeded. If possible, the code for the actual problem found when delivery was attempted should be returned rather than this code.