My trunk provider sip.xs4all.nl recommends re-registration every 3 minutes. I cannot change this interval on PBXes. The provider reports that PBXes sets the timeout at 1 hour. This is reasonable in my view but after 4 minutes or so the provider considers the connection lost and for the next 56 minutes sends all incoming calls to voicemail. It has been like this for a year or so. I had a workaround by diverting incoming calls to another number but cannot keep this.
connection times out at provider
