This is a new error message, but same issue as the prior "Failed to disable echo" message. While the error is Blynk generated, the issue is not caused by Blynk itself, rather improper connection and/or improper ESP firmware/setup
Double check that you have proper:
` Physical connection of the TX/RX pins - 3.3v to 5v logic level converter where required.
` Independent, and sufficient, 3.3v source for the ESP (NOT tapping off from the Arduino)
` Correct (current) firmware on the ESP
And here is some Arduino-ESP connection guides, as per the Help Center documentation (links at the upper right of this screen):