Soundiiz not connecting due to server delay

I’ve been using Soundiiz for over a year now to sync playlists between lastfm, Spotify, and Plex. It’s been working great, however in the last month Plex isn’t able to connect reliably to Soundiiz.

I can connect initially, it says its connected, remote access is working fine. Then when I either refresh playlists or a sync starts, Plex disconnects.

I’ve gone through the Remote Access troubleshooting for Plex and there doesn’t seem to be any issues with that (Remote Access is working completely as I would expect), in all other aspects Plex is working just fine.

I’m not sure where to go next to find the issue and fix it, as far as I can tell nothing has actually changed in my set-up. I’ve asked on the Soundiiz forum and was advised that the issue is because Soundiiz is unable to ping/reach my server at all or not in an “acceptable” delay.

Any advice or tips on how I can get this up and running again? I’d love to be able to sync across all my various music servers again.