Question
What values does Twilio accept for the Min-SE (Minimum Session Expires) SIP header?
Product
Programmable Voice, Elastic SIP Trunking
Answer
Twilio requires a minimum value of 120 for the Min-SE header.
Some PBXs default to a value of 90, which is the lowest value allowed by standard SIP RFCs. However, if a value lower than 120 is provided, Twilio will reject the call with a 422 Session Interval Too Small response.
To resolve this, ensure your PBX or Session Border Controller (SBC) is configured to use a Min-SE value of 120 or higher.
Additional Information