SIP
422 Session Interval Too Small
The request's Session-Expires value is too small. The Min-SE header in the response indicates the minimum acceptable session interval.
When You See This Code
When using SIP session timers (RFC 4028) and the proposed session refresh interval is below the server's minimum.
How to Fix
Increase the Session-Expires value to at least the value indicated in the Min-SE header of the 422 response.