Hello, I'm getting build errors for invalid app id when building using either the new win 8.1 phone preview or the legacy windows phone build. I've attached a screenshot of the legacy error.
The problem seems to be coming from the number prefix on the app id. App id in the image is fake, but it was giving the same error for my real id which has the 5 numbers as a prefix. I copied this id directly from my windows developer dashboard so I'm pretty sure the value is right.