Vet and behaviourist here. Don't use Star's method. Intimidation and fear can be extremely effective at training, but generally create other more long-term behaviour problems even if these are not immediately apparent, and are terrible for welfare. Also, I'm assuming that you've chosen to have a pet as a companion, rather than a fear-driven automaton? In which case you'll probably want your dog to respond to you because it understands the concept of where to toilet rather than just trying to avoid your anger. The method described above is about 20 years out of date and shows a total lack of knowledge about animal welfare, dog behaviour, physiology or learning theory.
OP - great that you've already checked for a UTI - this can occur after first season and may be causing bladder sensitivity that is triggering the issue. Once toileting in the house occurs, there is an element of learning, reinforced by the scent profile that can maintain this behaviour. Firstly clean the area well with biological washing powder solution - do not use ammonia based detergents.
Give her frequent access to toilet outdoors (as often as you can, ideally every hour or two and always after a feed or a nap) and praise her each time she does so, just as you did when she was a pup. Make sure she gets a couple of opportunities to toilet after her evening meal (again praise when done in the right place). You'll need to go outside with her (not clear if you already are or not), and remember the world can be a scary and distracting place for a small dog so she may need some reassurance.
Its worth persisting with crate training - don't lock her in! Put her bed and treats in there and let her choose to enter and come out when she wants. Only when she is totally relaxed in there should you close the door for a few minutes, then gradually build this up over a period of several days. Dogs won't toilet in their sleeping area unless desperate. An alternative is to use a baby gate/close doors to restrict access to the area where she's started toileting.
Toy breeds are difficult to toilet train and can regress with stress or anxiety so DAP diffusers in the room may help too.
A combination of lots of praise for appropriate toileting behaviour and restricting her opportunities to toilet in the wrong place will facilitate her learning - this article has some useful tips for small dog training
www.aspca.org/pet-care/virtual-pet-behaviorist/dog-behavior/living-small-dogs