Xero Data refresh in Service

[Housden996]

Hi all

I have managed to connect to my companies xero API via the custom connector, extract and automatically update the bearer token in Power BI Desktop using the following M Query:

let
authUrl = "https://identity.xero.com/connect/token",

formBody =
[
   grant_type = "client_credentials",
   client_id = "xxxxxxxxxxxx",
   client_secret = "xxxxxxxxxxx",
   scope = "accounting.transactions.read"   
], 

AuthResponse= Web.Contents(authUrl,
[Headers=[#"Content-Type" = "application/x-www-form-urlencoded"],Content = Text.ToBinary(Uri.BuildQueryString(formBody))]),

AuthJson = Json.Document(AuthResponse),
    #"Converted to Table" = Record.ToTable(AuthJson),
    token = #"Converted to Table"{0}[Value],

bearer = Text.Combine({"bearer", token}, " "),
    Source = Json.Document(Web.Contents("https://api.xero.com/api.xro/2.0/CreditNotes", [Headers=[#"xero-tenant-id"="xxxxxxxxxxx", Authorization=bearer, Accept="application/json", #"Content-Type"="application/json"]])),
    #"Converted to Table2" = Table.FromRecords({Source}),
    #"Expanded CreditNotes2" = Table.ExpandListColumn(#"Converted to Table2", "CreditNotes"),
    #"Expanded CreditNotes" = Table.ExpandRecordColumn(#"Expanded CreditNotes2", "CreditNotes", {"CreditNoteID", "CreditNoteNumber", "Payments", "ID", "HasErrors", "CurrencyRate", "Type", "Reference", "RemainingCredit", "Allocations", "HasAttachments", "Contact", "DateString", "Date", "Status", "LineAmountTypes", "LineItems", "SubTotal", "TotalTax", "Total", "UpdatedDateUTC", "CurrencyCode"}, {"CreditNoteID", "CreditNoteNumber", "Payments", "ID.1", "HasErrors", "CurrencyRate", "Type", "Reference", "RemainingCredit", "Allocations", "HasAttachments", "Contact", "DateString", "Date", "Status.1", "LineAmountTypes", "LineItems", "SubTotal", "TotalTax", "Total", "UpdatedDateUTC", "CurrencyCode"}),
    #"Changed Type" = Table.TransformColumnTypes(#"Expanded CreditNotes",{{"DateString", type datetime}}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Changed Type",{{"DateString", type date}})
in
    #"Changed Type1"

So when I manualy refresh data in the desktop report this works.

I have published this to Power BI service and now I am getting a connection error when I try to connect the gateway with no real error code or message to help me resolve the issue. 

I have attempted anonymous organizational wich I am using in PBI Desktop as well as the the service principal in Power BI Service which doesnt work as well. I have this working for the MS Graph API as well as our service desk providers API just not this one.

Can any one notice any stand out issues which could be causing the gateway to fail/a fix?

Thanks in advance!

Alex