The module name already exists, but it doesn't actually exist.

The module name already exists, but it doesn't actually exist.

I try to add a new module with the name 'Hotels'. It does not allow me to add the module. It says: 

This module name already exists. Please enter a different name.

So, I go into the Modules list and I search 'Hotels'. A module with the name Hotels does not exist. 

So, how can I create this custom Module?