REST Interacting with BigCommerce from VB EXCEL - vb.net

Question

NOTE: Further research (and thick skin, and lots of coffee) has lead me here where it suggests that the store cannot receive the uid and pwd in the URL, and I gather from the PHP examples here that the transmission needs to be encrypted. Is this my problem? If so I have not been able to find anything on how to work around this.
I would be happy if the open() command prompted the UID & PWD window to open and I can manually input the values. Does anyone have a suggestion. Thanks!
I am learning how to use the BigCommerce APIs and I am programming in VB / XL to be able to directly post / retrieve from all fields in the store's DB.
I have never coded on this before (although I get around VB OK) and I am stuck. I have the following code:
Const URL As String = "https://www.myurl.com/api/v2/brands.json"
Public Sub Test()
Dim xmlHttp As Object
Set xmlHttp = CreateObject("MSXML2.ServerXMLHTTP.6.0")
xmlHttp.Open "GET", URL, False, "myid", "mytoken"
xmlHttp.setRequestHeader "Content-Type", "application/json"
xmlHttp.send
Dim html As MSHTML.HTMLDocument
Set html = New MSHTML.HTMLDocument
html.body.innerHTML = xmlHttp.ResponseText
Range("A1").Value = html.body.innerHTML
End Sub
What I get back is "401" or more precisely:
[{"status":401,"message":"No credentials were supplied in the request."}]
The credentials are valid and working, as if I place the URL in my browser and submit it, the pop up for UID & PWD comes up, and once I place the values I am using in the code, the resulting BRANDS list appears in the browser.
Additionally, if I add a "rand num" to the URL to ensure the returned data is not cached as suggested here, then the request looks like this:
xmlHttp.Open "GET", URL & "&t=" & WorksheetFunction.RandBetween(1, 99), False, `"myid", "mytoken"`
and the response back from BC changes to:
406</STATUS><MESSAGE>The requested content type is not available.</MESSAGE></ERROR></ERRORS>
I have also tried this (where UID and PWD are the correct values):
xmlHttp.Open "GET", URL & "&user=UID" & "&password=PWD", False
and i get:
406</STATUS><MESSAGE>The requested content type is not available.</MESSAGE></ERROR></ERRORS>
Can anyone help me understand pls. I have followed examples at MSDN, but I am still stuck. The BC API site is poor in examples (none actually!) for VB.
Thank you

Answer 1

Sorted! BC required this:
Set xmlHttp = CreateObject("MSXML2.ServerXMLHTTP.6.0")
xmlHttp.Open "GET", URL_Cat, UID, PWD
xmlHttp.setRequestHeader "Content-Type", "application/json"
xmlHttp.setRequestHeader "Authorization", "Basic " & Base64Encode(UID & ":" & PWD)
xmlHttp.send
I got Base64Encode code from here. Hope this helps someone.