Zingotel change expire to 600 from 900

[yawarabbasp]

Hi

I have configured zingotel on 3cx and it keep trying to register. After analyzing debug info Zingotel asked me to change Expire from 900 to 600. see the debug

Max-Forwards: 70
User-Agent: SIPPER for 3CX Phone
Expires: 900
Content-Length: 0

what is the procedure to change this time to 600

Thanks