Need help with TTS/Casting to Chromecasts on VLANs

I know these questions have been raised before but none of the solutions seem to work for me. I have the following rules setup in Unifi Routing

The weird thing is often, TTS will work once and then stop working. Similarly, Aircast (which I have installed as an addon in HAOS) also doesn’t work. it will initiate the playback but there will be no sound from the speakers.

My understanding is the above should work (and I also changed the internal url of HAOS from automatic to hardcoded IP:8123 in case that was the issue but that didn’t seem to help.

Any pointers appreciated!