Getting an error when using HypModifyConnection to update the report connection

Summary:

Trying to use HypModifyConnection but getting this error message:

Code Snippet (add any code snippets that support your topic, if applicable):

Private Declare PtrSafe Function HypModifyConnection Lib "HsAddin" (vtDocumentName, vtSheetName, vtGridName As Variant, vtServer, vtURL, vtApp, vtDB, vtConnParam) As Long

Sub Macro1()

' Macro1 Macro

Connection_String = Range("D5").Value

  'modify url in a particular workbook for all SV sheets

  s = HypModifyConnection("Change Connections.xlsm", "Sheet2", "", "", Connection_String, "", "", "")

End Sub

The cell D5 contains the server connection string:

When I run this macro, I'm getting an error message - see above. I tried to remove Sheet2 and the file name, to update all sheets in the workbook, to no avail. Same error code.