User reported a failure of one of our Blazor Server apps an hour or so ago. When I investigated it seemed the Azure SignalR service was responding with "502 Bad Gateway" to the initial OPTIONS on the signalr hub negotiation (signalr is separate to the webapp that hosts the site)
In azure manpo, this shows for the SignalR service:
Restarting it does not succeed. Clicking "view activity logs" in the "the resource is ina failed state" banner simply brings a "Code: 'invalidRG'" message
The only significant event recently on this subscription was that it converted from a Free-Trial to Pay-as-you-go and there were some issues transitioning (upgrade done post subscription disable for lack of payment method, took some time to get it reactivated), but then everything seemed to work well for a day
There are many other services in the same resource group, apparently working fine - it's just SignalR. The "Azure status" page shows that all SignalR services are in "Good" condition.
Where does one go from here to diagnose and fix this? Is it a "pay for support from MS and ask them"?