Server issues Please Help

ive currently been trying to add modded cars to my game but i keep getting a popup message. im new to this whole server thing so im a bit confused. the message at the top of the window says “Game something error happened”. then the lower part says "System.ArgumentExeption: An item with the same key has already been added.
at System.Throwhelper.ThrowArgumentException(ExeptionResource resource)
at System.Collections.Generic.Dictionary’2.Insert(TKey Key, TValue value, Boolean add)

That is what the first row says. if you know what is happening please let me know i really want to get these cars in this server so me and my friend may enjoy it.
Please and thank you
~NuclearServers Official

Hello! This is quite an easy mistake to make. Please go to your folder with all the models and check if any of them have the same name as another. An example would be “fbi.yft”. Double check all your models, if they are ALL different let me know and we can figure something else out.