"Check spelling as you type" does NOT work most of the time

My auto-correction is on. However it doesn’t work most of the time (I mean = If I make mistakes I don’t see the read underline).

When this happen, I have to shut down the computer and re-open it (and interrupt my creativity process). SOMETIMES this fix the issue.

Do you have any other suggestion? A Refresh/sync/something? This is becoming a big issue for my productivity.

Thanks

Solved (see attachment)