Why do all the other faction leaders refuse to deal with me?

For a number of turns now, all the other faction leaders have refused to consider any deals I might want to offer them. It doesn't matter whether I have a bad or good relationship with them, every single one is telling me they are not going to do deals with me at this time. They continue to offer me deals though.

Does anyone know why this is? What can I do to change this?


Oops, turns out this was a silly question. The reason I can't trade any more is because there are only a limited number of deals you can make, and I've hit my maximum.