Frigate Integration - Clips don't play in HA only regardless device

Apologies if this is in the wrong place, but I figure it’s probably something I’ve missed rather than a bug. Couldn’t find similar elsewhere.

I’ve got Frigate running on an old desktop and HA on my server. If I connect to Frigate directly from my phone I can play clips.
Via HA, whether on my phone, or desktop, I cannot play clips.

Frigate is on CCTV VLAN, HA has interfaces on CCTV VLAN, my personal VLAN and our work VLAN.

Edge://media-internals gives the following error:

MediaSource endOfStream before demuxer initialization completes (before HAVE_METADATA) is treated as an error. This may also occur as consequence of other MediaSource errors before HAVE_METADATA.

Player just keeps reloading about twice a second with the same error.
Snapshots work fine.