Azure VM Losing Network Connectivity after Doomain Removal

I currently have Azure VM domain joined servers running Server 2019 Std which are being upgraded via an in-place upgrade to Server 2025 Std.

After the upgrade I will be un-joining from the domain and then joining a WORKGROUP to allow Entra ID joining of the servers.

I have completed this on a non-critical server but upon removing from the domain the server appears to have lost network connectivity and displays a Computer Icon with a flashing cable, then eventually fails.

I noticed the Ethernet displays now “Public” so I changed back to “Private” and removed “Network Level Authentication” from RDP.  I also removed the Custom DNS server settings that were on the NIC in Azure Portal and set to “Virtual Network Inherited” to allow Azure DNS.

Unfortunately, the same events occur time and time again with no network connectivity.  I have reset the NIC and network via Powershell and CMD commands as suggested in most Google searches along with recreating the VM NIC in Azure, but still the same!

Does anyone have any idea what could be causing the issue and how to resolve it as someone must have experienced similar in the past when unjoining an Azure VM from a corporate domain?

I have been directing all traffic from server via the Azure FW using a Route table with a route directing all traffic via Azure FW and associating the subnets being used:

Address Prefix: 0.0.0.0/0 - Next Hop type: Virtual Appliance – Next Hop IP address: <IP of Azure FW Private IP>

I assume this would remain the same too?

Please any advice or suggestions would be greatly appreciated?

Thanks