This is despite the fact that the serial is copied from the Adobe order history.
Moreover, when I click on the "Contact Us Real help from real people." in order to resolve this Adobe problem, the only thing I get is the same useless pages (https://helpx.adobe.com/contact.html) which only suggest that I download and register the software, which I've already have.
Having me running in cicrles has been very frustrating to say the least.
not much you can do about a serial number flagged as fraudulent unless it's a current adobe product and a lr with serial number is not current.
if you're seeing an invalid serial number message, that's different:
assuming you're using a valid adobe serial number (6 groups of 4 numbers), you have a mismatch between your installation file and serial number. ie, you can have a valid serial number, but if it's for program A and your installation file is for program B, you will see an invalid serial number message.
common mismatches are language/region (eg, serial number is for western europe and installation file is eastern europe), platform (eg, serial number is for a mac and installation file is win), license type (eg, education vs enterprise vs individual). and one of the most common is using a program installation file with a suite's serial number. eg, using a cs6 suite serial number with a photoshop cs6 installation file. that won't work even though photoshop is included in that suite. you must use the (correct) suite's installation file (and you can choose to only install one program from the suite).