The license file contains a ‘signature’ to verify the license has not been changed. You are inadvertently changing the license file; there are subtle differences between Linux text files and Windows text files. (In particular, Windows uses CRLF while Linux uses CR only.) You don’t need to know the details, but even opening the file in Notepad and then saving it again is changing the file!
This time go to your mail client and save the attachment directly from the message (without opening in Notepad) to the PBX. Your license should then work fine.
