Http client error when connecting to VM via Azure Private Link Service

Hello,

I have a client that is using Azure Private link service behind an Azure load balance for their application. One of their vendors stated they are experiencing intermittent drops and they dont received any traffic on their VM. Below is the error the client is getting on their end when the connection fails. We did a packet capture, and we see reset (RST) for the VM. But based on the error below, it doesn't appear to be networking related. Can you provide some Insight for this error?