PiHole from VM, can't RDP to host

[Rich_T]

I just set up Pi-hole using DietPi on a VirtualBox on a Windows 10 host PC, and it works great. I am not using it for DHCP, I just have my router using it's static IP as the DNS server.
I frequently RDP to this host machine both from inside and outside my network, and have not previously had any issue doing so.
The problem I have now is that once the VM with Pi-hole is running, if I try and RDP into the host Windows 10 machine, everything locks up (host and the VirtualBox VM). The rest of the network continues working, as the router then just uses the secondary DNS server but the VM and host, even if accessed via the keyboard, are locked up and require a reboot.
I'm guessing it's some kind circular DNS issue (RDP in, host does dns lookup which goes to router, which points back to VM on host, which goes back to router...?) but I don't understand how/why, or (obviously) how to fix it. The lockup happens whether I'm on the local network or outside it when I RDP.
Any help or troubleshooting advice would be appreciated.

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[technicalpyro]

first thing i will ask is have you set the VM to have a different IP from the host machine?

[Rich_T]

Yes - Host 0.107; VM 0.163
I don't think it's relevant, but I do use a different port (3391 as opposed to 3389) for RDP.

[Rich_T]

This is not a Pi-hole, VM issue and I'll attempt to delete. The computer was updated to 1903 on Friday, and that apparently is causing the issue. I shutdown and stopped the VM from starting and it still has the same issue. I can RDP once. The second time it locks up the host.
Sorry for the post without checking this, I've been RDPing to it for years and never had the issue, so assumed it was the last thing I did.

[Rich_T]

Confirmed - rolled back to 1803 and all works as expected.

[technicalpyro]

No need to delete it will automatically get closed in 21 days. We're glad you found the solution and as other may have similar issues this will remain searchable