181 1xx Provisional RFC 3261
SIP 181 Call Is Being Forwarded
The call is being forwarded to another destination.
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Common causes
- Call forwarding on the called party or a redirect inside a PBX.
How to fix it
- Informational only. Use it to trace forwarding loops when calls take unusually long to connect.
Seeing 181 on calls through a router or firewall? Check that SIP ALG is disabled. It causes a surprising number of SIP errors. Read why.
About 1xx responses
The request was received and is being processed. The call is not finished yet.