Sony ILCA-77M2 - Manual (Page 198)

You cannot send AVCHD movies to a smartphone. Set [ File Format] to [MP4] to record movies.
[303] Troubleshooting Troubleshooting Wi-Fi
[Ctrl w/ Smartphone] or [Send to Smartphone] is
canceled halfway.
When the remaining battery level is low, [Ctrl w/ Smartphone] or [Send to Smartphone] may be
canceled halfway. Charge the battery pack and try again.
[304] Troubleshooting Troubleshooting Wi-Fi
The shooting screen for [Ctrl w/ Smartphone] is not
displayed smoothly./The connection between this
product and the smartphone is disconnected.
Data communication between this product and the smartphone may fail due to signal conditions.
Place this product closer to the smartphone.
[305] Troubleshooting Troubleshooting Wi-Fi
You cannot use One-Touch connection (NFC).
Place the (N mark) on the smartphone and the (N mark) on the product as close together as
possible. If there is no response, move the smartphone a few millimeters or move the smartphone
away from this product, wait more than 10 seconds, and then touch them together again.
[Airplane Mode] is set to [On]. Set [Airplane Mode] to [Off].
Check whether the NFC function is activated on your smartphone. For details, refer to the instruction
manual of the smartphone.
Do not place any metal objects other than a smartphone near the (N mark).
Do not contact two or more smartphones to this product at the same time.
If another NFC-based application is running on your smartphone, terminate that application.
[306] Troubleshooting Troubleshooting Computers