ERROR:GAMEOBJECT: The collection 'xxx' could not be created since there is already a socket with the same name.

You have two collections with the same name.

1. In the assets panel, double click a collection.
2. In the outline panel, click, 'Collection'.
3. In the properties, the 'Name' will be the same as another collection in your assets. It is likely that you have more than one called 'default'.
4. Change the name of the collection to something more meaningful.