Why can't I recruit new followers?

[Sebah]

I've been playing for a long time now on my battle mage character and after a while I noticed something that I really don't know how fix. All this time I've been playing I recruited only Lydia and Odvar the Afflicted and all it was fine. After a while I started to get stronger (only playing on expert) so i went on solo for a while but when the game became to easy I started playing on master but i needed a companion so I wanted to hire a new follower so I went for Uthgerd but to my surprise I didn't have the option to brawl with her so I couldn't recruit her. I've tried other followers and i've noticed that the dialogue line that let's me hire them is missing. I've tried again Lydia and Odvar but they work just fine, I tell them to follow me and they do. I can dismiss them too. It's just the new companions that I've never used before that are bugged and I don't know what to do because I really don't want to reinstall the game and all the mods all over again. The only mod that I use and that alters the followers it's UFO. I've ran BOSS and it found no problems. I've even disabled UFO and made a clean save and still nothing. I've also tried the "set playerfollowercount to 0" and it din't help at all. Anyone has any ideas or has seen this happening before. Please help.

[LaEspada]

This happens quite a bit even with my own game. Normally restarting skyrim sometimes fixes it for me. And if you really want to make them a follower just use console commands to had them to follower faction.