I'm sure you've already checked it, but this has happened to me before if my trainer is out of date.
If you've purchased any new DLCs or anything recently, it might be a good idea to download the latest version of the trainer again and see if that helps.
You can try hiring some prostitutes if there are some, pretty easy as they're hiding you all the time. Apart of that I have no idea.
Even if you activate the trainer at the main menu?