My friend can’t join

Hi. I’m trying to play EAFC24 with some friends. I’m playing on a ps5. My other friends are playing on ps4 and Xbox one. Everything works fine, but when my friend on a ps5 tries to join, he can’t. 
we tried everything, and everything is up to date. 
When we check eachother in the friends menu, it just says “friend cannot be invited”. 
we don’t understand. Please help.