OpenForm Method Help "The OpenForm action was canceled"

[Ayo]

Where is the error in the this? Thanks.
Private Sub cmdConfig_850GSM_Click()
If Me.txtGSM850_Vendor <> "" And Me.txtGSM850_BTS <> "" Then
Me.Visible = False
DoCmd.OpenForm "frmSiteConfiguration"
Else
'Me.cmdConfig_850GSM.Enabled = False
End If
End Sub