Silence on external phone number forward

Ive tried forwarding calls at night time to our cell phone, the phone rings fine but it is silent on both ends. All other function of asterisk are working fine, outbound routes etc. But bridging from an sip truck to an sip truck or a zap truck to a sip truck (DURING A FORWARD TO AN EXTERNAL EXTENSION ONLY ie 5555551234#) are both producing the same result. Silence.