What are the some reason why a mark cannot be registered?

A mark cannot be registered for several reasons, including if it is too similar to an existing registered trademark, which could cause confusion among consumers. Additionally, marks that are merely descriptive of the goods or services they represent, or that are generic, may be denied registration. Marks that are misleading, deceptive, or scandalous can also be rejected. Lastly, if the mark has not been used in commerce or does not meet the necessary legal requirements, registration may be denied.