Can't add script behaviour TMP_CoroutineTween. The script needs to derive from MonoBehaviour!

My scripts were working fine last night.
This morning I can’t attach any scripts to my gameobject.
Even the scripts that are already attached, when removed, cannot be attached back onto thegame object.
I get this error “Can’t add script behaviour TMP_CoroutineTween. The script needs to derive from MonoBehaviour!” .

I searched online and it seems it is the naming convention of the script.
I have made sure, all my scripts have scriptname : Monobehaviour in them so I’m pretty sure this is not an issue.

Any help would be appreciated. Scripts were working fine last night.

I think you may already fix the problem. Anyway, I just also meet the same problem, and I check the console, it gives me some error, then I fix the error and the scripts can attach again. So if you still do not get the point, you can try my way.