It’s possible, but before you contact them, I’d try a refresh of your network to be sure it isn’t a local issue.

Unplug all your Sonos devices from power. While they are unplugged, reboot your router. Once the router comes back up, plug the Sonos devices back in. Wait a couple of minutes, then test that process again.  If it continues to fail, it’s likely the issue is at their end. If it works, you had a local issue, and I’d give some consideration to reserving IP addresses fir your Sonos in the router’s DHCP table….although if the issue happened again, the unplug/reboot process would work, too. 

This is not a network error. Why?
1. I only play Primephonic to my ethernet-connected devices, as the wireless devices won't reliably play their high bit-rate stream.
2. I don't get this issue from any other service.
3. I get the error just using the "add to end of queue"  option. no playback occuring.
4. It is only certain areas of the Primephonic interface that has the problem, like my saved albums. Other areas work fine.
If no one here has a better suggestion, I'll contact Primephonic. They are a relatively new service and have had many problems with their Sonos interface.
 

Yes, that’s what you ought to do. Primephone already acknowledged that bug but also stated that they won’t fix it for the time being. Not enough (personell) resources available to allocate I guess.