Plex uPNP giving error message

Hi, I used to use Plex software as a uPNP server with my music stored on a WD MycloudEX2Ultra network drive to stream to my Arcam SA30. In the past few months when I try this using mConnect on my iPhone I always get the error message “Notice - Device sent an error response”.
Also I can’t seem yo get Musiclife to work at all now.
I can still stream using Twonky Server on my WD drive, but Twonky is out of support so while it’s OK it’s not ideal.

Can anyone tell me why Plex no longer works? (It use to be fine.) Alternatively is there a recommendation for a uPNP server that will run on my WD network drive?

Try increasing the uPnP TTL hops in your router settings, and you may want to experiment in gradually reducing the advertisement period also. Increasing the former did the trick for me.

Thank you. But this is a bit beyond my technical expertise. Would these settings be in my Google wifi hub or my Virgin Media broadband router? I can’t find them on either.