VB Code to restrict opening excel file for certain computer name only

Hello:

Please refer to attached file.
I am trying to put the code in the workbook so that the excel file can be open only if the computer name is as assigned.
However, it is malfunctioning although i have correct Computer name (User as below) in the code.
Would appreciate if you can help me with this to solve

1st set of code is in "ThisWorkbook"

Private Sub Workbook_Open()
    
     'Unhide all worksheets
    Application.ScreenUpdating = False
    Call XQuit
    Call ShowAllSheets
    
    Application.ScreenUpdating = True
End Sub

Below code in Module

Sub XQuit()
    Dim User As String, passWord As String
    User = "NBook;" 'separate with ";"
    
    
    If CBool(InStr(1, User, Environ("computername") & ";")) Then
    
    MsgBox ("Workbook is enabled")
    
    
         'workbbok is enabled show its content
    Else
    MsgBox "You are trying to access restricted panel.", vbCritical, "Access Denied"
    
        passWord = InputBox("Password for Manual Access:", vbCritical, "Automatic Access Denied -  Last Chance")
        If passWord <> "1111" Then Application.Quit
    
    
    
    End If
End Sub

Sub ShowAllSheets()
     'Show all worksheets except the macro welcome page
     
    Dim ws As Worksheet
     
    For Each ws In ThisWorkbook.Worksheets
        If Not ws.Name = WelcomePage Then ws.Visible = xlSheetVisible
    Next ws
     
    Worksheets("Macros").Visible = xlSheetVeryHidden
End Sub
Sub HideAllSheets()
     'Hide all worksheets except the macro welcome page
    Dim ws As Worksheet
     
    Worksheets("Macros").Visible = xlSheetVisible
     
    For Each ws In ThisWorkbook.Worksheets
        If Not ws.Name = WelcomePage Then ws.Visible = xlSheetVeryHidden
    Next ws
     
    'Worksheets(WelcomePage).Activate
    Worksheets("Macros").Activate
    
End Sub

Let me know if you have any questions.
Thanks.
Riz