Alarm no longer setting itself?

I found this after a bit of a duckduckgo search. The last post on this thread may help

https://howtomendit.com/answers.php?id=303675

Ftheueu
November 2020

Sorry. The alarm is a Altex. 20 years old and not sure of the model number.

Neil
November 2020

Yes. Here's a suggestion.

You didn't bother to state the make and model, so we can't go searching for the manual, read it and then post the answer (probably with a disparaging observation that you could have done that yourself in the first place)

So: Make? Model?

Not a clairvoyant
November 2020