can not have muti-play

When I was playing online with a friend, I entered his map, but short lines appeared many times and this interface appeared. I have tried restarting, re-downloading, changing devices, and even using the same wifi with friends face-to-face, but it still doesn't work. However, if my friend adds a new map and I enter it, or let him enter my map, there is no such thing. question. I didn't have this problem before, it just started appearing this week. What problem did you encounter? How should I solve it? thank you.