Add domain button is not selectable

If the link under domains is not clickable then the hosting space has the rights of 1 Top level domain.

Add domain button is not selectable

If you want to add a Top level domain then you can place an order for a domain only package and put it in the comments of the order:
Please place under my existing package.

Then this will be added and you can use the domain. This is basically always an action that is performed by us.

If you have further questions you can always see if someone is present on the online chat.
Or you can create a ticket for this in the customer panel.