Apple Store glitches leave some unable to reserve the iPhone 14, over 3 hours after pre-orders started

Pre-orders for the iPhone 14 and iPhone 14 Pro commenced at 5 a.m. PDT., however, over three hours later, some customers are still unable to complete the pre-order process due to issues with the online Apple Store, namely the iPhone Upgrade Program which is showing an error message that the reservation service is unavailable.
Customers in the United Kingdom attempting to reserve an iPhone under the iPhone Upgrade Program for in-store pickup are facing a roadblock on Apple.com, which halts customers after they select their desired model and configuration with a message saying “We’re sorry, but this service is currently unavailable. Please check back later.”
Shipping estimates for the new devices have quickly slipped into October for most, if not all, colors and configurations, with Apple.com showing very few Apple Store locations offering launch day pickup options for the new devices, which will be delivered to lucky customers who managed to grab the first wave of pre-order stock beginning Friday, September 16.
Minute-by-minute, iPhone 14 supply is dwindling from Apple and third-party retailers.
It isn’t uncommon for pre-order stock of Apple’s new products to quickly sell out, however, the situation has been made worse due to the earlier online Apple Store issues, which resulted in many missing out on launch day availability due to payment errors, Apple Store check-in window slots, or a delay in the Apple Store becoming available after it was temporarily pulled in the hours leading up to pre-orders beginning.
In some cases, customers were shown error messages saying they had reached their reservation limit, before even ordering any products. In other cases, customers would get to the check-out page, and then be thrown back to the main Apple Store screen, resulting in them loosing their chosen pick-up slot.
As with all Apple pre-orders, launch stock availability is limited, and many have reported that the technical issues have resulted in them not being able to pre-order the model or configuration they intended.