I got a project (Arduino uno connected to ESP8266 and some other Hardware).
In general it works but I got some Problems with Blynk loosing connection because Buffer overflow that happens sometimes frequently, sometimes not once for over an hour (it's not related to flooding the server).
I now thought it might be related to the serial monitor, so I closed it.
But as soon as I close the serial Monitor my Arduino stops working entirely.
On my Arduino the RX LED is flashing, afterwards 2 or 3 times the Pin 13 LED. this repeads until I start the serial monitor again. Then it does work as before.
What does this mean?