REST API CALL in function wont work due to invalid input

My function looks like the following.

= (playerId as text) as table=>
let
    Source = Json.Document(

        Web.Contents(
            "https://api.greatAPI.io/v1/",
            [
                RelativePath ="players/" & (playerId)
            ],
                [
                    Headers=
                    [
                        Accept="application/json", Authorization="Bearer XXXXXXXXXXXXXXX"
                    ]
            ]))
in
    #"Source"

Error Message:

Error in query ''. Expression.Error: 3 arguments were passed to a function that expects between 1 and 2 arguments.
Details:
    pattern=
    arguments=[list]

 
The input playerId:

xd7u2cf3-5412f6-4b0d-r300-a8bss41c7cda

I tried various header syntax but nothing seems to work.
As the error says 3 argmuments where passed is wrong because just one argument is passed, I assumend that somehow the "-" make a problem.
Tried also to but the playerId into "" or ''.
Nothing worked so far.