I've deployed .net application on Azure App service which works perfectly fine including webSync connections when I access it through custom domain or app service default domain, but only WebSync doesn't work when I enable the Azure Front Door and points my domain to go through Front Door to the backend app service.
My WebSync is running from a Azure VM and all the required ports are allowed, app service and VM are sharing the same VNET.
I am using Azure Front Door's "Standard" version, Do I need to switch to the premium version and connect with my app service through private link? but again my WebSync is running from a VM so it's not clear to me that why Azure Front Door is unable to connect with WebSync and all the other things are working fine.
Azure Front Door only supports HTTP, HTTPS and HTTP/2.
https://learn.microsoft.com/en-us/azure/frontdoor/front-door-faq#what-protocols-does-azure-front-door-support-