https://www.theverge.com/2017/10/24/16533288/iphone-x-apple-shipping-problems-half-2017

The holy grail for many Apple fans, the iPhone X, has been plagued by production issues that already look to substantially limit supplies of the coveted device. Now, a new report from the Nikkei Asian Review clarifies just how much they’ll be limited: Apple will apparently ship only 20 million units this year, half of how much it had planned. The report suggests the reduction in units comes from technical issues surrounding components that are used in the new face authentication feature.

According to Nikkei, at the beginning of mass production for the iPhone X, there were defects that occurred in the OLED panels during the bonding process. Though that was fixed in July, there continued to be problems in assembling the module responsible for face authentication. The report states that manufacturers were only able to improve the number of good units made at the end of September, cutting it quite close to its planned release date of November 3rd. Around 10 million iPhone X units are being manufactured each month, according to the report, though Apple is believed to be in negotiations for additional production for some parts.