Hello @Andrew_Webb,
Thanks for letting me know that unplugging the iPhone has resolved the issue.
We have had a previous report describing similar behavior to what you’re seeing and we’re going to do some testing as to what could be causing this issue, I will be sure to update you on our findings.
As for the “File Loading Slowly” errors you are experiencing, is there anything exotic happening on your network that would cause it to perform differently than expected? Are you by any chance using a VPN anywhere in your current setup? If you temporarily connect your affected devices directly into your router do you still experience the same behavior? Do you by any chance have a firewall active on the Mac OSX?
Please let me know when possible.
Thanks,
Noris