Tvheadend

I have a issue with clients accessing the tvheadend server over the network.

Setup is as follows:

HTS Tvheadend 4.2.8-36 running on Ubuntu 18 with a Hauppauge DVB-C tuner recognised as Sillicon Labs Si2168

This server is running primarily on "VLAN 1" the primary VLAN in my network using subnet 192.168.1.0/24

I have 2 clients:
Nvidia Shield using Dreamplayer client
Raspberry Pi using Kodi Tvheadend PVR client

Both clients run on VLAN 20. There is firewall rules in place on a Edge router. These rules prevent communicating VLAN 20 with VLAN 1 but allow communication from VLAN 1 to VLAN 20. I have added 1 specific rule to allow port 9981 on the Ubuntu server to be accessed by the entire VLAN 20 subnet.

However when i try to run the setup on the Dreamplayer i get a error:
Server connection failed to the provided port. Please check your settings. Make sure the extension 'webinterface' or "OpenWeblf" is installed and enabled and you are using the right port address.

When i change the Shield on the switch to VLAN 1 i get access without any issue and i can watch TV. As soon as i switch it back to VLAN 20 i get this error message again.

Until yesterday i ran TVheadend on a raspberry pi using kodi. This worked fine with the clients in a different subnet/VLAN so i am almost certain this is a setting in the new tvheadend setup.

Attached a screenshot of the current settings. I have also tried 0.0.0.0/24 for example. Same result.

Does anyone here have any suggestions?