494 4xx Client error RFC 3329
SIP 494 Security Agreement Required
The server requires a security agreement mechanism (Security-Client or Security-Server headers), common in IMS.
Advertisement
Common causes
- IMS or VoLTE networks requiring IPsec agreement.
How to fix it
- Enable sec-agree on the client, or use the correct IMS profile.
Seeing 494 on calls through a router or firewall? Check that SIP ALG is disabled. It causes a surprising number of SIP errors. Read why.
About 4xx responses
The request has a problem or cannot be completed at this server, usually because of something on the requesting side or the target user.