Andrew29
You can try Adobe Chat, but I do not believe it will give you any support on this matter because you are not dealing with the current version which for now is version 12/12.1. Coupled with that is the situation where this is not a serial number/program activation matter. It is a feature activation issue. Different story.
There have been several what seemed like insurmountable problems in this regard, especially with MPEG2 Activation and Premiere Elements 8.0 and versions earlier than 8.0/8.0.1. But some have solved the problem with
- uninstall the program via the usual Control Panel/Programs way
- do a free ccleaner run through (regular cleaner and registry cleaner parts) https://www.piriform.com/ccleaner/download
- reinstall the program with antivirus and firewall(s) disabled.
Please let us know if any of that works for you also.
Thanks.
ATR