Cannot connect to world on Minecraft PE 1.16.210?

So me and my friend were trying to play Minecraft together. A few days ago, it worked, and we were easily able to connect to each others worlds. Now today, and yesterday, we haven't been able to. It keeps saying "unable to connect to world." Our wifi connections are both good, so why is it doing this? We're both on the same version as well so it can't be that either.

Any help would be greatly appreciated

:)