[Resolved]Error while copying one Worksheet multiple time to a new Workbook

[Fr0mi]

Hello everyone and in advance thanks for your help!

Well, basically I the aim is to copy a model worksheet from one existing Workbook to a new Workbook, changing its name and populating it with whatever data.
Next Step copy the model Worksheet from the Old Workbook to the newly created one and simply add it as a new Sheet. (In the end there should be two Workbooks one with a model Worksheet and the other with X Worksheets)

Now, I have already done this for a previous project and it works perfectly fine. (Using the same Workbook)
I now have to do something similiar but using different Data & different Sheets.
However now I adjusted the codes made a new form & function to do this which now gives me a runtime error..
The code to copy the Sheets however is exactly the same as before the only change happened in the name of variables..

If WBCheck = 1 Then ' Check if this is the first time copying a worksheet
          ' Copy and Create new Workbook
          OldWB.Activate ' Old Workbook
          Traffic.Copy ' Model Sheet
        
          ' Define Variable for newly created Workbook & Sheet
          ' Copy function should set focus to new Workbook & Sheet
          Set NewWB = ActiveWorkbook
          Set NewSheet = NewWB.ActiveSheet
          WBCheck = 2
Else
          OldWB.Activate ' Focus Old Workbook again
          ' Copy new Sheet into the Workbook that has been created earlier
          ' Copy Model Sheet "Traffic" Again to the New Workbook
          ' & Change its Name to the Next Name in the Array "ColabsArray"
          Traffic.Copy After:=NewWB.Sheets(ShortName(ColabsArray(NI)))
          Set NewSheet = NewWB.ActiveSheet ' Set Variable for newSheet
End If

I keep getting the runtime error on this line
Traffic.Copy After:=NewWB.Sheets(ShortName(ColabsArray(NI)))

I have checked that "Traffic" & "ColabsArray" & "NI" all have a valid value.
"NewWB" I don't know how to check..
I am guessing there is a problem while defining the "NewWB" variable!

Thanks for everyones help!!!