@NicolaO63
I suppose you bought this router as new, from a store. If you have difficulties login its WebGUI follow this FAQ.
If you have registered a TP-Link ID and bound your cloud router to it, the login password you created here will be invalid. Please log in to the cloud router using your TP-Link ID account.
If you are using a TP-Link ID to log in, or you have enabled the Password Recovery feature of the router, click Forgot Password? on the login page and then follow the instructions to reset it.
Final step in this FAQ is to contact your local tech support with the issue description and request for assistance.
By the way you don't have to open a different thread for the same kind of issue - troubleshooting the issue wouldn't be consistent enough.