Can't Connect

[MarkVista]

We've been running WVD for a few months.  Our users regularly (once or twice weekly) receive an error "Cannot connect no available resources".  What resource does this indicate needs to be increased?  Memory on the host machine?  Something else?

[#2]

@MarkVista 

That error indicates that there aren't any Hosts in an 'available' state. It doesn't necessarily have anything to do with the actual CPU or Memory usage. Try checking their status in the Host-pool next time this happens:

Make sure the checkmark is green and the machine isn't in a Drain-mode

You can of course always check the metrics themselves to see if the machines are congested and are malfunctioning because of that to make sure.  With regards to what resources are important for a Windows 10 WVD; always deploy a machine with at least 4CPUs if you want to avoid general performance or other usage issues.

[#3]

I've also seen this error message when using the Scaling Automation solution. If your scaling isn't aggressive enough, users will see this message until a new session host is turned on by the Scaling Automation solution. So if you choose the default of 15 minutes, there could be 15 minute gap where users can't connect. You can test different values for the "SessionThresholdPerCPU" and "RecurrenceInterval" to try to work around this issue. For the "RecurrenceInterval", the smallest recommended value is 5 minutes and that's for small WVD deployments. Also, its worth mentioning, the SessionThresholdPerCPU value can be a decimal number.