Moved door sensor, now alarm won’t arm – any ideas?

Hello,

We have just moved a door sensor for a powermax complete, moved onto another door. And now the alarm won't arm.

No warning messages are coming up (and when we took the sensor off and battery out, no phone call was made to my mobile which it normally does if the alarm sounds) so I'm confused.

It just says “not ready” and “back door not closed” even though the sensor flashes and the two bits seem to recognise each other when close to each other.

Given I’ve moved the sensor (not changed the battery – it doesn’t say low battery so didn’t bother to change it), do I need to re-set the whole system or something?

Any thoughts would be greatly appreciated as it seems like probably a simple issue to resolve without having to call somebody out!

Thank you in advance.