Trying to simply add a record/bottom row or duplicate but its says "you cannot create a new record because it is configured that no one can add a new record? with a lock sign

Hi to anyone so grateful.

I gone through every setting and cannot change the setting so I canadd a record/bottom row or duplicate because its says "you cannot create a new record because it is configured that no one can add a new record? with a lock sign in the bottom left.

I have tried unsynching, changing permissions and checked the plan but no luck at all.

Any step by step ideas are so welcome?
Thanks