New Incoming Calls Not Being Picked Up By 3CX For A Minute Or So

[Jim.Lloyd]

I am noticing that if I call my 3CX PBX from my cell, the first time rings right through. I hang up, wait a few seconds and redial... testing. The SIP trunk doesn't immediately acknowledge a call coming in. If I let it keep ringing, the call will come in through the SIP trunk after about a minute. I am using this at home and just never have had two calls in process.

I did put in a new Synology RT6600ax router, and spent some time working out the settings needed to properly have the 3CX PBX actually work. I am not sure if it is a setting I did not quite properly set, or if maybe it is something the Synology RT6600ax does as part of an anti-hacking or denial of service protection. It shouldn't normally affect me, but I may help a friend change out his old Cisco RV320 router. I would not want suggest this to his office have this issue cause them to scrap the router.

Thank you for any help.

 

[Jim.Lloyd]

OK to close this one...

What I am seeing appears to be a security response by the Synology RT6600ax router... possibly denial of service or IP flooding related, or maybe my SIP provider was experienced the Sunday night "maintenance thing". I had someone call me from two different cell phones, today. They both came in just fine, overlapping calls. I'll have to try having them call, hang up after 40+ seconds, then call right back. I am thinking if the same number calls me back in rapid succession that they will be ignored for a period of time on the recall.

 

[Jean-ChristopheC_3CX]

Hello,
Run a wireshark capture on the router and see if the invite arrive at the right time.