How do I fix this exception System.Runtime.InteropServices.COMException

when I try resetting my password  the UpdateUser method throws System.Runtime.InteropServices.COMException. how do I fix this:
code:

Private Function UpdateUserinAD(ByVal Username As String, ByVal firstname As String, ByVal lastname As String, ByVal password As String, ByVal phone As String, ByVal email As String) As Boolean Dim isupdated As Boolean = False Try < ...