Data source credentials greyed out due to dynamic source in Web.Content()

Hi, thanks for replying.

I've applied few things from the mentioned posts, sorry it took some time, but unfortunately i'm unable to solve this. 

Right now, the error is different, after installing a personal gateway.

Data source privacy settings are all the same (all set to Organizational). 

The code where the mentioned function is used is as below (i have left out the other steps, as they are just for transforming the data):

let
    Source = #"BE_Global",
    tCountryInfo_Table = Source{[Item="tCountryInfo",Kind="Table"]}[Data],
    ...
    #"Added Employee cost 2 EUR" = Table.AddColumn(#"Inserted Text Between Delimiters", "Employee Cost 2 EUR", each if [Employee cost 2] = null then null else fCurrency([Currency short])*[Employee cost 2]),
    #"Added Employeer cost 2 EUR" = Table.AddColumn(#"Added Employee cost 2 EUR", "Employer cost 2 EUR", each if [Employer cost 2] = null then null else fCurrency([Currency short]) * [Employer cost 2]),
    #"Changed Type2" = Table.TransformColumnTypes(#"Added Employeer cost 2 EUR",{{"Employee Cost 2 EUR", type number}, {"Employer cost 2 EUR", type number}}),
    #"Rounded Off" = Table.TransformColumns(#"Changed Type2",{{"Employee Cost 2 EUR", each Number.Round(_, 2), type number}, {"Employer cost 2 EUR", each Number.Round(_, 2), type number}})
in
    #"Rounded Off"

Source is the Excel file (BE_Global) located on SharePoint, which is retrieved by a web connector, and i'm just referencing it in this query.

By reading this post, i guess i'm combining two different sources which are not compatible:
1. Reference from the BE_Global

2. fCurrency function (web page shown in my initial post)

How can i workaround this hiccup?