c/p from NFPS
If you are getting the error message "Bad or missing Serial Number" is because your client / addon is misconfigured and is not providing the Serial Number to our servers which is mandatory.
If you are using another client / addon please search in the forum for instructions on how to setup the serial number on that client or simply migrate to one of the clients that allow it.
In case your Client / Addon allows you to specify a custom Serial Number it is highly recommended to use that option and create your own S/N with 13 random alpha numeric digits.
For those that are already sending the serial number but still getting this error please try re-linking (remove and add again) your MAC Address to your Donation number by using the following form:
All donations are valid only for 1 mac address and 1 device only.