I have the MSFS2020 and I also run Aivlasoft EFB. To keep Aivlasoft up to date I use Navigraph FMS Data Manager, however, having followed all the instructions i.e. turning off anti virus, Firewall etc and did a complete reload, I am still getting wrong email or password messages.
There are multiple email accounts with your name. Please check you are using the email/password for the account with your subscription. If unclear please, send email to account@navigraph.com