I had a heck of a time today trying to get some callers to connect to Vmix today. I'm using a fully licensed version of Vmix Pro on a powerful Win10 desktop with a wired high speed internet connection (~450Mbps down/20Mbs up). Up until today, I've had very little issues with Vmix calls and over the last several months done quite a few different connections with different people without issue.
Earlier I started Vmix up to prepare for a session today and everything seemed to be normal. I usually start up Vmix 15-30 minutes before a session so that I can make sure I have things configured. Vmix links are sent out in advance and assigned to specific people so that they line up properly with the inputs in Vmix.
While waiting I usually pull up the Call Manager so I can see when people start to join. Things looked fine. The call manager shows the Vmix call in passwords and links. While waiting I happened to glance over at the call manager and there was was a number of yellow lines showing an error "System.Net.WebException: The operation has timed out" for each of the vmix numbers.
A quick Google search brought up this thread: https://forums.vmix.com/...-system-net-webexception
Which then mentioned issues with the Vmix servers.

Using another system to test and call in to one of the links and it connected fine. I didn't think anything of it as it looked as though there was no problem.

A few minutes later some callers were able to call in just fine and had solid connections.
A few of the callers were not. They were able to click the vmix links go to the vmixcall site enter their names...but were just shown a blue video return and their own camera in the corner.
The call manager showed their attempt: "Caller has made initial contact!" and "Sending our reply to initiate the call..." but nothing further and the call never completed connecting.
I had similar but intermittent results trying to call in from another system or a phone connected either to my wireless or
After a while it seemed to work fine for myself and others who had previously been able to connect.

We had the callers check to make sure they were not on a VPN, were using Chrome or Firefox and tried different vmix numbers, generated new ones. I had no success in getting these callers connected.

I've read over the call troubleshooter: https://www.vmix.com/kno...on-issues-with-vmix-call

But nothing seems to be really addressing the issue. I'm at a loss what to do next.