Visual studio code syntax check

I’m using visual studio code with the openhab plugin.
Currently the syntax check doesn’t show any code issue anymore (problems tab below).
This was working before.
What to check / configure to get this working again?

Most likely you have an empty tab because there are no problems.
To be sure click the X in the right corner of the terminal window (Within Visual Studio)
If the Problem Tab reappears then there is a problem in parsing the problem to the terminal.