Getting error on applying UDID as "Please enter a valid UDID"

Question

Even though I've entered a new valid UDID to my developer's account, I'm getting an error "Please enter a valid UDID" so I can't proceed from there. Here I've enclose the image.

Answer 1

It sounds like you're getting the wrong number for the UDID. My process for doing this is to:

1. Connect the phone I want to add to my Mac while I have Xcode running.
2. Agree on the phone I can trust this computer and put in my passcode to verify that.
3. Open up "Devices and Simulators" window in Xcode from the Window menu.
4. Copy the number with the label "Identifier" and use that in the Apple developer account portal.

If you have a paired Apple Watch, it'll show on the same Devices screen in Xcode as the phone it's paired with in the section just below the header.

I hope this helps.