Volvo S80 2.4 1999 Start prevented try again message

[Volvo S80]

Hi all,

My father`s 99 S 80 today showed an message "Start prevented try again" and did not crank at all, battery voltage was 12.4 Volt radio and other things work.

We took the key out and tried again it started without problem, from my experience it will start to show it more often in the near future as always with Volvo. From what I read on forums most cases it is the the key ring antenna, should I buy one or wait a bit more?

Thank you for your time!