I need to be an Add on Vehicles

'You have too many vehicles pending for validation, please wait some time that moderators can approve your previous contributions'

That's what it says

Well the answer is in the message: you have to wait some time that moderators can approve new vehicles.
That limit was added because you add too quickly too much stuff on the site, we can't follow.

How long do I have to wait?

That someone has time to validate new contributions...

He has nothing in the pending list currently.

I approved one title right before I went to bed last night, and that was the last one he had.

So I suppose he can add new ones?
Or there is a bug?