Multiple sites having issues parking, answering calls

[GregoryCCC]

I work for an MSP. We manage multiple sites where we have deployed 3CX and we also use it internally. At least 2 of our clients are experiencing the same issues we are. The two sites use on-premise Windows machines to host 3CX while we are cloud hosted with Google. Intermittently we have issues parking/picking up parks and answering calls. This happens when we are no where near our simultaneous call limit. It doesn't seem to depend on whether or not there are any other simultaneous calls. Quite simply, when pressing the shared park BLF it will appear as if the call has been picked up on the phone but it has not. The caller is still parked. We've found that if you end call and answer over and over eventually it will finally work. Sometimes pressing answer on an incoming call simply doesn't work. Sometimes it "works" and the outside caller can hear us but we can't hear them.

Earliest report August 20, 2020

Phones used: Yealink T42S, T46S, T54W; Polycom VVX 400

Sites range from <10 to around 30 phones

All in north GA, USA but quite a ways apart.

We've tried 3CX updates, SIP trunk updates, reboots, OS updates, firmware updates and reprovisions. We've triple checked QOS where appropriate. Sometimes these things will help temporarily but issues come back. We've halted making any changes or updates to other sites at this point. Would love to know if any others are experiencing this or a good direction to go in.

 

[Alphabetic]

So it happens for both locally hosted and hosted installs?

what is the network topology at affected sites?

Are phones on supported templates with the latest firmware?

can you replicate the problem?

does it happen if you use the 3CX app or webclient.

 

[GregoryCCC]

So it happens for both locally hosted and hosted installs?

what is the network topology at affected sites?

Are phones on supported templates with the latest firmware?

can you replicate the problem?

does it happen if you use the 3CX app or webclient.

Thanks for the response! My answers below in red.

So it happens for both locally hosted and hosted installs? Correct

what is the network topology at affected sites?
The two remote sites use Windows server for DHCP, and are using Comcast voice lines on Windows hosted 3CX (one physical, one Hyper-V VM). We use cloud hosted 3CX and very basic network (firewall, switch) with firewall doing DHCP. All use Sonicwall as default gateway and have phones/wired PCs on the same LAN. Hopefully that's the answer you're looking for.

Are phones on supported templates with the latest firmware?
Site with Polycom phones is using a custom template my boss created a while back, well before this issue. Yealink phones use the standard templates under "supported". Edit: Firmware updated multiple times since the issues started.

can you replicate the problem?
It happens often, no pattern we've been able to figure out.

does it happen if you use the 3CX app or webclient.
None of us use the webclient but I've been using the 3CX app as a work around. It doesn't seem to have a problem picking up parked calls so that I can answer them with my deskphone.

 

[Alphabetic]

Are your sites all using a SonicWall and does your 3CX pass the firewall test?

 

[GregoryCCC]

Are your sites all using a SonicWall and does your 3CX pass the firewall test?

I'll correct my earlier statement; the Polycom site isn't using a Sonicwall. Other locations are using a Sonicwall. I just ran the firewall checker on our site (Sonicwall) and it passed everything without issue. The other locations probably haven't been run since deployment. I can do them after business hours if needed.