User_defined_connection example won't work

Hello!
I’m trying to experiment with custom connection. The problem is it simply doesn’t work.
As far as I understood it sould work exactly like the Serial_USB connection.
I have Arduino UNO and a single button widget operating built-in LED on PIN 13. The IDE is 1.6.6.
With the SerialUSB everthing works ok: I run the proxy-script on my com3 port, the android frontend runs ok and the LED responds to my button.
But with User_defined_connection example it doesn’t work. I load the example sketch, change only auth key, then run the sctipt and nothing happens. The script loops in connecting/disconnecting.

Connect(“cloud.blynk.cc”, “8442”) - OK
InOut() START
DSR is OFF
Received EOF
EVENT_CLOSE
InOut() - STOP
Disconnect() - OK
Connect(“cloud.blynk.cc”, “8442”) - OK
InOut() START
DSR is OFF
Received EOF
EVENT_CLOSE
InOut() - STOP
Disconnect() - OK
Connect(“cloud.blynk.cc”, “8442”) - OK
InOut() START
DSR is OFF
Received EOF
EVENT_CLOSE
InOut() - STOP
Disconnect() - OK
Connect(“cloud.blynk.cc”, “8442”) - OK
InOut() START
DSR is OFF
The android frontend says there is no connection to my hardware. The LED doesn’t respond.
What am I doing wrong?
Btw. is it needed to check connection status in code? The [connected] variable seems to be always true in the example sketch…

Yes, it’s always connected because the serial connection is always ready to send/receive.
Please enable #define BLYNK_DEBUG so you can see actual Blynk communication.

Ok, thank you. But before digging into debug I just would like to know: should the user_defined_connection sketch work “out of the box” like serial_USB, or not? Mine does not as described above.

Update: I tried the debug port, I get following output:
[1] Blynk v0.3.1
[2002] Login timeout
[2025] Login timeout
[2049] Login timeout
[2072] Login timeout
[2096] Login timeout

[2494] Login timeout
[2518] Login timeout
[2541] Login timeout

That means, the Blynk.begin() shows the lib version. Then the first Blynk.connect() fails after 2 s. Then it keeps failing in loop. Actually it misreports timeout, while there can’t be timeouts each 25 ms.
Btw, I placed debug messages within BlynkStreamRead and BlynkStreamWrite, but never saw them in the debug output. That means that custom functions are never called when establishing connection, and that’s very strange.

Any ideas?

I think there may be a problem… need to re-check it

Thank you. Please inform as soon as you find anything out.