482 4xx Client error RFC 3261

SIP 482 Loop Detected

The server received a request that already contains its own address in the Via path. The request is looping.

Typical Q.850 / ISDN cause: 25 (Exchange routing error)

Common causes

Two systems routing a call back and forth (for example, PBX to carrier and back again).
Wrong default routes or call forward loops.

Trace Via headers to find the loop, and fix the routing so each side has a terminating route for the number.

Seeing 482 on calls through a router or firewall? Check that SIP ALG is disabled. It causes a surprising number of SIP errors. Read why.

The request has a problem or cannot be completed at this server, usually because of something on the requesting side or the target user.