My friends can't receive an invites from my world.

I want to play with my friends in mobile we are the same version 1.17.10.20 Beta. But when i was invite him his offline but he says he playing minecraft online that time. When i invite him he said that he did not receive an invitation from me. Please help me, I've been searching this issues. I think its a bug. I just want to play with him, i already activate my multiplayer. We are friends in minecraft already.