As of January 13, 2023, a subscription purchased in SongPop Classic will ONLY work in SongPop Classic. In order for your subscription to work in both SongPop Classic and SongPop you must purchase a subscription in SongPop. 

To ensure you have the correct accounts connected, please go to Edit > Account Settings > Linked SongPop Account and check that the email and username match your SongPop account.