Just to follow this up since there are no replies in case anyone has a similar problem. I opened a support ticket and they told me to uninstall and reinstall the app. I did and I have not had the error again.
The amplifi remote app gives me this when I search for tones especially if I haven't searched for a bit (30+minues?) and I have to login again. Can this time be increased or automated? It wouldn't be so bad if it remembered the username and password but I have to type it in each time. TIA