Error while trying to play multiplayer

I try to play with my partner in Minecraft PE, however, most of the time we try tells us that the server cannot be located. There have been few times that it has allowed us, however, it usually does not allow us to connect
I have already tried several ways, such as clearing cache, data, uninstalling the game, closing the account and opening it, changing Skin, and removing resource packages, however, the failure persists