I don't have any account there so I could not check. However, try this. It should work.
Sub GetLoggedIn() Const Url$ = "https://my.bexio.com/simplesaml/module.php/core/loginuserpassorg.php?client_id=7753313026.apps.bexio.com" Dim Http As New XMLHTTP60, HTML As New HTMLDocument Dim auth As Object, authval$, payload$ With Http .Open "GET", Url, False .send HTML.body.innerHTML = .responseText End With Set auth = HTML.querySelector("form[name='f'] input[name='AuthState']") authval = WorksheetFunction.EncodeURL(auth.getAttribute("value")) 'put your username and password in the following line replacing xxxx 'make sure to replace "@" with "%40", as in [email protected] with something%40gmail.com payload = "username=xxxxxxxxx&password=xxxxxxxxx&AuthState=" & authval With Http .Open "POST", Url, False .setRequestHeader "Content-type", "application/x-www-form-urlencoded" .send payload End With MsgBox Http.responseText End Sub