You are using PF3 version 3.0.0 and need to update to the latest release otherwise it will not work with FS2020. If you've just purchased PF3 the you have simply just loaded the bas product. It does say in the emails you received to 'Check for Updates' once installed.
Once installed please use the 'Check for Updates' button on the main display to ensure you have the very latest updates.
Please either use 'Check for Updates' from the main menu or download the cumulative updates package from the top of this forum