Just because Sony has halted pre-orders for the Sony Xperia Z2 doesn't necessarily mean that there is a problem that is slowing down production of the phone. There is also a chance that pre-orders for the handset have swamped Sony's ability to produce the handset. After all, the model is one of the most eagerly awaited Android phones.
The big question is how long it will be before Sony puts its new flagship model back up for pre-orders. The phone is expected to be launched this month in Korea and in Japan which means it was supposed to hit the market before the Samsung Galaxy S5. The latter is scheduled to launch on April 11th. But just a few days ago, there was a report stating that the Xperia Z2 release could be pushed back to late April, or early May. If this speculation comes true, Samsung will get the jump on Sony after all.
Sony removes the pre-order button from its listing of the Sony Xperia Z2 on regional Sony Store websites
source: XperiaBlog via AndroidAuthority