I have gfi outlets in each of three bathrooms, and they just stopped working yesterday. They are controlled by a GFI circuit breaker in the main circuit breaker panel. The breaker has not tripped. I tripped it, then pushed it to the off position, then reset it. It did not help. I repeated the procedure. It still did not help. I used a test probe, and the probe light went on, but no devices (hair dryer, night light) would work. These devices work fine when plugged into non GFI outlets. I then replaced the GFI circuit breaker in the main panel. The result was the same problems as stated above.

I have gfi outlets in each of three bathrooms
What does that mean? Does it mean you have GFI outlets in the bedrooms, they have the Test and Reset buttons on the outlet or does it mean that the outlets are GFI protected by being on the GFCI circuit breaker?

If the outlets have the Test and Reset buttons are you sure they are GFI outlets and not arc fault outlets?

Just for clarification, if you are using a GFCI breaker then replace the GFCI receptacles.

However, the smarter thing to do is replace the GFCI breaker and just use the GFCI receptacles.