2024 toyota prius xle door will not lock by holding handle

Where is the fob when you try this ?

 

Things to check:

- Are you putting your hand inside the door handle when you try? You don't have to do that to lock, only unlock. When locking, only touch the front part of the door handle.
- Is the car off? It won't lock from the outside if it's in Ready or Acc mode.
- Is there a keyfob in your car? If you got a second keyfob, make sure it isn't in there when you try to lock your doors.
- Is your phone in the car? If you set up your phone through Digital Connect, it acts like a keyfob. Also, if you wear your phone in a front pocket, you might need to go into the app settings and turn the sensitivity to low. Low is good for a front pocket, medium is good for a normal purse, high is good for an oversize purse full of stuff or a backpack. The size/thickness of a phone case can also affect this.
- Did you open a rear door around the time you got in? This gen of Toyotas have a safety feature to remind you there might be something(like a child) in the back seat. It's triggered by the rear door being opened and closed within a certain time window of the front doors being unlocked and the car started(I forget the details because it's a disableable feature and I turned it off within a couple weeks of ownership).

Start there and let us know if none of this works.

 

There's a groove in the front part of the handle, towards the engine. About where your thumb would fall if you put your right hand on the handle (driver side). You just need to touch this, not hold it - I run the back of my hand over it in a swiping motion when walking away, so it doesn't need to be a fingerprint touch.

As Hammer said grabbing the inside is what unlocks - so if you're putting your hand fully into the handle and trying to lock it, you're confusing the car by sending a lock and unlock signal at the same time.