Can you elaborate what device and what you’ve tried doing to fix it?
Like delete and reinstall the app, unplug router and tv for a few minutes.
Is this for live channels or on demand content?
Is that OVP_00012?
The normal reason for this is that you are in another country, not the UK, or possibly that Now think you are in a different country, or that you are trying to use a VPN, which Now don’t allow.
Try the various remedies found in this thread:-
and report back on the results.