In my case I was trying to use genymotion emulator device.
With genymotion opened and running, I’ve tried to run my app in this emulator but I it doesn’t worth
In this part I had this error:
'C:\Users\Jose\AppData\Local\Android\sdk\platform-tools\adb.exe,start-server' failed -- run manually if necessary
Then I’ve tried Jaskey’s solution but it doesn’t works.
So I stopped genymotion emulator.
Then I restart ADB (Tools > Android > Unchecked Unable ADB Integration then I’ve checked again)
Next I’ve start genymotion emulator again
And now the app works on the emulator.