H2 API search in PLAINTEXT using VB6?

[JohnPotier]

I'm using VB6 on Win11. My current project is about querying Discogs. I have registered the application with them, gotten the key & secret (strings). In my code I've come as far as checking if my (Discogs) token is missing and if it is, authenticate again.

I'm able to auhenticate, and have stored the token and secret (can be fetched with getOAuthToken(), getOAuthTokenSecret())

In the same session, just seconds later, I'm trying to search. Running the code below returns:
"401 - Unauthorized {"message": "You must authenticate to access this resource."}"

The code:

Private Sub cmdSearch_Click()
'getMyKey, getMySecret, getOAuthToken, getOAuthTokenSecret returns the strings for key, token and secrets
Dim sOAuthTimestamp As String: sOAuthTimestamp = Left(CStr(Timer * 86400), 8)
Dim sAuthorizationHeader As String, sSearchURL As String

    Dim xmlHttp As Object  '                     ' Declare and...
    Set xmlHttp = CreateObject("MSXML2.XMLHTTP") ' ...create the XMLHTTP object
    
    sAuthorizationHeader = "OAuth " & _
        "oauth_consumer_key=""" & getMyKey() & """, " & _
        "oauth_nonce=""" & getNonce(8) & """, " & _
        "oauth_signature=""" & UrlEncode2(getMySecret() & "&" & getOAuthTokenSecret()) & """, " & _
        "oauth_signature_method=""PLAINTEXT"", " & _
        "oauth_timestamp=""" & sOAuthTimestamp & """, " & _
        "oauth_token=""" & getOAuthToken() & """, " & _
        "oauth_version=""1.0"""

    'ie: https://api.discogs.com/database/search?artist=ABBA
    sSearchURL = getSearchURL(txtSearch(0).text, txtSearch(1).text, txtSearch(2).text), artist album title

    xmlHttp.Open "GET", sSearchURL, False
        xmlHttp.setRequestHeader "Authorization", sAuthorizationHeader
        xmlHttp.setRequestHeader "User-Agent", App.Title & "/" & App.Major & "." & App.Minor & " (Windows; VB6)"
        xmlHttp.send
    
    If xmlHttp.Status = 200 Then
        lblSearchResult.Caption = xmlHttp.responseText
    Else
        lblSearchResult.Caption = Now & ", error: " & xmlHttp.Status & " - " & xmlHttp.statusText & vbCrLf & xmlHttp.responseText
    End If
    Set xmlHttp = Nothing

End Sub

What am I doing wrong here?