An error occurred while saving the commentAnonymous commented
I had the same issue, I've spent some time try to troubleshot with Microsoft support and by my own.
My issue was happening from a Windows (IIS) environment.
I deployed the same app in a App Service (Linux) using same VNet and the issue was not happening there.
I've moved my app from Windows (IIS) to Linux (Same app service name) The issue persisted.
I'd tried to create a another VNet and the issue still happening.
I'd tried to redeploy the entire environments; Elastic Search, Network (with another subnet and IP) and dotnet 5 app, the issue was happening still.
I've removed the VNet for a couple of hours, after adding the VNet again the issue was no longer happening.
It's really hard to say here what have fixed it, I really don't know how it is the VNet lifecycle on Azure environment, but it seems that removing the VNet and adding it again after many hours has fixed the issue (As silly as it seems).