Hi @Mirddin 

Thanks for posting in our business forum.

You should check what protocols and what layer your webex device uses.

Either Wireshark and find out the concrete answers to both questions. Or check their support website about if there is anything needed.

BTW, does your WAN get a public IP?

Hi @Mirddin 

Thanks for posting in our business forum.

So, you probably need to consult this with your Webex support on this issue. What I can tell you is that all Omada routers are NAT4 and NAT type might be a problem for certain instant message software due to the protocols they use.
 

Refer to a similar post: https://community.tp-link.com/en/business/forum/topic/657418

Hi @Mirddin 

Thanks for posting in our business forum.

Mirddin wrote

  @Clive_A Well, in the end I've installed original ISP's router (Orange Funbox) with configured PPPoE, with disabled Wi-Fi and enabled DHCP. And plugged in TP-Link ER605 into Orange FunBox. On TP-Link WAN was configured as regular DHCP client. And the problem disapperared :(

 

I would be very surprised to know this.

First, this creates a double-NAT situation. It would only prove to me that this is not a NAT type issue. Nor IPTV for phone line issue.

It seems to be Internet protocol-based audio. Meaning it is like any other type of traffic. They should be not affected by any function on the router. It should be packed properly in TCP/UDP. So, it is not a problem with the router NAT and other stuff.

These are assumptions on this matter. Which so far no indications leading to the problem originating from the router.

Don't know if you have configured anything special on the ISP router. Or ISP requires to use their device mandatory.

It should be WIreshark to see what's wrong with it if you are still interested in that. Wireshark guide can be found on the official site, FAQ.