Lonesomeness is something that all humans (no matter who they are or where they live) know well. In a way, it connects us. However, the speaker of "Alone" warns that we cannot go through life all by our lonesome selves. Life will swallow us whole unless we've got family, friends, or a community of some kind to help us through the hard times.
Although "Alone" seems to worry that people are isolated, the poem itself actually breaks out of isolation by addressing other people.
There isn't any solution to the isolation described in this poem.