Arduino IDE 1.6.8, ESP8266-07 problem

I can not upload my project onto ESP8266-07.
In bottom string for messages of Arduino IDE I see “None on COM17”.
In device manager of PC the USB-UART TTL convertor is defined as COM17.
But if I choose board NodeMCU, then in bottom string for messages of Arduino IDE I see “COM17” - all is Ok.
What it may be?
Esp core 2.3.0-rc2,
Blynk library 0.4.1.