Cannot Join through Find Player (on my account)

Upon using the Find Player function, certain players including myself are not joinable.

Some of them show up as default accounts; 117 service tag, mjolnir emblem, chief 6 avatar. With no details on the player besides the name which is often uncapitalised?

Why does this happen and is there any way to fix it? It’s very frustrating trying to start a lobby when no one can join on you (and if the friendlist worked correctly, well it wouldnt be a problem.)