The iPhone 6 Plus marks Apple Inc. (NASDAQ:AAPL)’s first entry into phablet territory, and consumers must be intrigued. The company began taking preorders this week, and already buyers are finding that they’ll need to wait three to four weeks to receive their handset.

iPhone 6 Plus Supply Comes Up Short

iPhone 6 Plus preorder deliveries pushed into October

Apple will make the iPhone 6 and the iPhone 6 Plus available for purchase on Sept. 19, so those who preordered early through Apple’s online store in the U.S. will receive their smartphones on that date. However, iPhone 6 Plus buyers in the U.S. now will have to wait three or four more weeks to get their phones, while buyers of the 4.7-inch iPhone 6 will still be able to receive their phones on Sept. 19 (at least as of this writing). In other countries, the story seems to be the same.

While many are assuming that extreme demand is to blame for the quick sell-out of the iPhone 6 Plus, there is also the possibility that Apple is dealing with supply constraints. Last year, the gold model of the iPhone 5S sold out pretty quickly, and it was believed that supply constraints were to blame.

Analysts debated back and forth whether the gold iPhone 5S was so much more popular than the other two colors or whether supply constraints were the problem. We could see a similar debate this year with the iPhone 6 Plus, particularly because of rumors about manufacturing problems with the battery and the thinness of the device that could have delayed the smartphone’s release.

iPhone 6 preorders don’t go smoothly

It hasn’t been a smooth road for Apple since it placed both of its new smartphones up for preorder. The company’s online store kept crashing. Some weren’t able to even get on the website at all, while others weren’t able to complete their orders, according to Mashable.

Even some mobile carrier websites started to crash, according to USA Today, as consumers sought the new iPhone 6 or iPhone 6 Plus. Some consumers had trouble accessing Sprint Corporation (NYSE:S)’s, Verizon Communications Inc. (NYSE:VZ)’s and T-Mobile US Inc (NYSE:TMUS)’s website and completing their purchase.