I’m sorry to hear that you’re having trouble with Azure SignalR Service.
I understand you have tried multiple steps isolate the issue and the issue occurred without any specific changes, kindly try the following steps to further narrow down the issue:
Azure SignalR service provides live trace tool to expose service traces on connectivity and messaging categories. Please see How to capture service traces - The traces include but aren’t limited to connection connected/disconnected events and message received/left events.
Also, if you haven’t done it already, kindly capture and review the network trace.
Additionally, please check Service Health and Resource Health status for more info.
Azure Service Health provides you with a customizable dashboard which tracks the health of your Azure services in the regions where you use them Azure Resource Health helps you diagnose and get support for service problems that affect your Azure resources. It reports on the current and past health of your resources.
Troubleshooting guide for Azure SignalR Service common issues
Kindly let us know how it goes, I'll follow up with you further.
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