RestSharp call to eBay oauth2 user token - vb.net

Question

I am trying to get eBay user tokens for my users using the identity api. I finally got it to work in Postman. Converted the call from Postman to a restsharp call from a vb.net test app. The Postman call works, the VB call returns "404 Not Found". Looked at the two calls using Fiddler. The only difference I can see is that the Postman call goes to:
"POST https://api.sandbox.ebay.com/identity/v1/oauth2/token";
and the VB app call goes to
"POST https://api.sandbox.ebay.com/identity/v1/oauth2/token/1"
It would appear that somewhere the VB app is appending "/1" to the api url. Not sure where this is occurring as I can step through the code as it executes and don't see it.
Is there a property in RestSharp that might cause this value to be appended?
EDIT added code. This code is supposed to return a user token and refresh token from eBay. It is taken pretty much from Postman with mods to work with the latest version.
Async Sub RSGetCode(sCode As String)
Dim client As RestClient = New RestClient("https://api.sandbox.ebay.com/identity/v1/oauth2/token")
Dim request As RestRequest = New RestRequest(Method.Post)
sCode = WebUtility.UrlDecode(sCode)
With request
.AddHeader("Content-Type", "application/x-www-form-urlencoded")
.AddHeader("Authorization", "Basic TXVycGh5c0MtNzYxNy00ZGRmLTk5N2ItOD..........................")
.AddParameter("grant_type", "authorization_code")
.AddParameter("code", sCode)
.AddParameter("redirect_uri", "Murphys_Creativ-Mu...........")
.AddParameter("Scope", "https://api.ebay.com/oauth/api_scope/sell.inventory")
End With
Dim responce = Await client.PostAsync(request)
'Dim responce = Await client.ExecuteAsync(request)
Dim sR As String = responce.Content
End Sub```

Answer 1

I got it to work by slightly reformating the code. See below.
Async Sub PostRestCode(sCode As String)
Dim client As RestClient = New RestClient("https://api.sandbox.ebay.com")
Dim request As RestRequest = New RestRequest("identity/v1/oauth2/token", Method.Post)
With request
.AddHeader("Content-Type", "application/x-www-form-urlencoded")
.AddHeader("Authorization", "Basic TXVycGh5c0MtNzYxNy00ZGRmLTk5N2ItODc2OGMzZWZkYT..............................")
.AddParameter("grant_type", "authorization_code")
.AddParameter("code", sCode) '"v^1.1#i^1#I^3#p^3#f^0#r^1#t^Ul41Xzg6NEN.......................................")
.AddParameter("redirect_uri", "Murphys_Creativ-Mu......................")
.AddParameter("Scope", "https://api.ebay.com/oauth/api_scope/sell.inventory")
End With
Dim responce = Await client.PostAsync(request)
'Dim responce = Await client.ExecuteAsync(request)
Dim sR As String = responce.Content
End Sub