The issue has nothing to do with the Pixnub activation limit. That won’t cause the installer to not run. The installer doesn’t even check for a license key. So it should still install. It only looks for a license key after it is installed when you run it. Then, it will just run in trial mode until activated.
However, the install issue may have to do with having multiple operating system accounts. The other occurrence I’ve seen with this was from a user who has multiple accounts. Adobe keeps the plugins installed on a per user basis in different folder paths. With multiple accounts, it could be confusing creative cloud when it tries to install. Or there could be a security issue on the OS or Creative Cloud side.
In any case, this is not an issue due to Pixnub licensing. I know that for 100% sure. So don’t mention that to the Adobe India support technician….. because they look for any excuse they can to end the chat and close out the ticket.