You should contact your Autodesk reseller and they will be able to search that serial number to find out if it goes to a different application or version. Most of the occurrences I've seen like this is almost always related to incorrect versions.
Hope this make sense.
HI Brandon and welcome to the community!
Confirming what Darren said in that invalid serial number errors are typically associated with using license information that has been upgraded to a newer version.