How to configure Asterisk to support emergency call for more than 20 seconds?

we use UE client to make emergency call. Asterisk works as IMS and called party. But we find Asterisk will bye the call 20 seconds after the call is setup. Can we configure the call duration time to more than 20 seconds?

Please explain UE and IMS and provide logging at sufficient detail to show why Aserisk is terminating the call.

20 seconds doesn’t seem to match any commonly used timeout in Asterisk although it is commonly used in user provided dialplans as a no answer timeout for sending calls to voicemail, etc. If this the cause, it is self inflicted.