Permit required.
The point is, ANY valid permit will do. Utah does not issue permits to persons under the age of 21. So that leaves any other government entity that DOES issue to persons under 21, namely Maine. If you happen to have one issued by the town of Plymouth, New Hampshire, that's good enough. That's why it doesn't specify where it must be issued. ANY government entity will do.
And that refers to loaded (ready to fire) OC. Unloaded carry (as described above and elsewhere) does not require a permit, subject to other locational restrictions.