I have an automatic Mondeo from 2019 and today the start stop has started to act up, whilst I was at a stop the engine went off but as I tried to pull away it didn’t restart and asked me to put it in ‘p’ for a manual restart,

 

when I restarted the engine, it started fine but the Auto Start/Stop was saying ‘’Not Available” rather than “Normal Operation” I was wondering if someone could shed some light on this for me,

 

thanks in advance 

Search this forum for well over a few hundred answers on the subject.

Short answer is check the SOC of your battery which is most likely below 70%

 

As above, also the owners handbook (available on line if you don't have one:  https://www.ford.co.uk/support/owner-manuals ) gives many reasons for non-operation.

That said, the usual thing is the start/stop not shutting off the engine, not the other way round.

I had the exact same symptoms in a previous car (non Ford) and it turned out to be an internal fault in the starter motor.

As @unofix suggests, check the battery and charge if necessary. If that sorts it, you're fine, if not further investigation may be needed.

Incidentally, we don't know what engine/transmission you have, which may affect the answer.