Thank you for the update!
Since the issue is limited to just one Facebook account and you're able to access Spades Plus using another account or as a guest, it strongly suggests that the problem is account-specific rather than related to your device, browser, or network.
It’s likely that there’s a connection or permission issue between your Facebook account and Spades Plus. I recommend reaching out to Facebook Support to check if there are any blocks, restrictions, or permission settings that might be affecting access to the game.