It probably is a GFI breaker. They don't last long. Only about 5 years before they need replaced.

GFI breakers (and AFCI breakers) will have test buttons. If you find any of these turn them off and then back on. This is how they are reset. Often, it's not obvious that they are tripped.

If you find this, label it so next time you don't have to use the trial and error method.

Hunt around for GFCIs in other places as well. There's no limit on what garage and outdoor outlets are connect to (as long as they aren't on circuits designated 'no other outlets' like the ones in kitchens, baths, and laundries). An unfinished basement or utility room is a prime suspect area (I had a brand new townhouse that had the GFCI for the outdoor and garage receptacles there).

If the house is older, it may be that all the GFCI receptacles including the bathrooms are on the same SINGLE GFCI. So if the house is older... check the ones in the bathrooms and the like. One apartment I was in had the sole GFCI for the entire place out on the balcony.

I'll have to disagree with the "GFI breakers dying after five years." I've never had one fail but I suppose there are some cheaper ones. I've certainly had GFCI receptacles (usually cheap ones to begin with ) fail even sooner however.

When we sold our last house the GFI breaker was flagged by the inspector as a bad . We did even know it went bad since the plugs still worked. The inspector said they usually only lasts 5 years. It was no big deal my hubby just popped a new one in.

Home inspectors are largely ignorant of electrical issues. In fact, other than a bargaining chip post signing, they're fairly useless. They pretty much disclaim all liability for failure to find unsafe things or identifying things that aren't legitimately issues. Now if they would warranty their bogus findings, I might think better of them.

As for the GFCI, unless it fails to trip when you push the TEST button, there's no reason to replace it just because "it's old." I've had GFCI breakers from several manufacturers (Square D, CH, GE) for over a decade without any sign of failure.

Second the idea of checking indoor outlets. My mom's house (1978) has bathroom and outdoor outlets on one circuit. Also make sure that any breaker that looks OK is not actually tripped. You have to switch it from Tripped to all the way Off then back to On.