My friends and I are trying to play in a world together.

I am on a PS4. My friends are all on PCs, using minecraft for windows 10. 

All of us have Microsoft accounts and we are friends on there. When we go to add friends to world, one of two things happen.

1) If I send the invite, they never receive a notification. 

2) If they send an invite, I get a notification and try to join but it gives me a error saying the world is not joinable. 

I have looked everywhere for answers. If anyone could please help me I would greatly appreciate it. I have played with other PS4 friends without problems but now that I'm trying to play we PC users I'm having issues.