My friends do not show up as online, so I cannot join their game. They are not appearing offline on their account.

My friends are online playing on Minecraft Bedrock (ps4), and I am on PC. When I go onto my xbox companion or I try to invite them to a game, it shows that they are online,. But when I try to join their game, it says there are no joinable friends. This has happened almost every time I have played in the past week.