Unifi Express and VOIP dropped calls

We have a small business using a Unifi Express router and a U6-LR access point, here is a map of the network


There are 48 devices connected to the UniFi Express Router (both WLAN/LAN).

The problem at hand is they’re dropping calls after 1-3 minutes; LAN and wireless. They have both desk phones and they use the Zultys app on their smartphones for incoming/outgoing calls; and the provider is American Telephone.

Things we tried are:

  • Logged into Unifi console/Settings/Security/Firewall Rules/Unchecked “state timeouts” auto. Set UDP from 160 to 600.

  • Click settings > Security > Firewall Rules > next to “Conntrack Modules” I removed H.323. NOTE: There’s no feature called SIP ALG on this UniFi Express router. According to the instructions it says to switch off/delete SIP and h.323. Since SIP was already removed, I ignored this step. If they still say there’s issues with their phones, then add it, and have them try again.

  • Click settings > Security > Traffic Rules > Create > click Allow next to Action > select Domain Name next to Category > enter domain name: “mxvirtual” (w/o quotes) and click Add > click “Select Device or Network” and choose “All Devices” > select Always next to Schedule > enter Description: “American Telephone VoIP” (w/o quotes), click Add Rule

  • Click Allow > select IP Address next to Category > enter IP, click Add > click “Select Device or Network” and choose “All Devices” > select Always next to Schedule > enter Description: “American Telephone VoIP” (w/o quotes), click Add Rule

We talked with a tech from American Telephone and we have implemented all the recommended settings from them.

Does anyone have any other recommendations?

1 Like
  1. Have you checked to see if your ISP is having issues?
  2. Has everything worked fine up until now?
  3. Has there been any changes on the firewall or router leading up to this point?

Is the UX Express powerful enough for your requirements? I’ve seen a few posts on other forum sites questioning what the units are capable of. I know they state 60 devices on the spec. Have you contacted Unifi support?

Have you turned off device and traffic identification to determine impact, what is the UX CPU load?

How is the other AP connected, wired backhaul, looks like it from the pic?