Hey guys,
I know it´s no Blynk spezific question but maybe someone can help me on. Now since some weeks I can not longer upload any sketch on my Wemos D1 mini`s. Usually it appears the message/error
Leaving…
Hard resetting via RTS pin…
and the buildin LED blinks on beat
I just waited for hours, nothing happend, reinstalled the Arduino IDE 1.8.9, installed older Arduino versions, upgraded al libraries, tried to upload other “simple sketches” but now I am helpless. Oh wait… I also googled a lot 
Try pressing and holding the reset button when you connect the power to the Wemos, then releasing the button and uploading a clean sketch.
Pete.
I still have the same issue with my last Esp32.
I never solved !
I got refund from the eBay vendor. 
No, still the same issue 
I assume that nothing is connected to your Wemos except the USB cable, and that you’ve tried other USB cables and USB ports on your PC.
What do you see in your serial monitor if you set it to the default for your Wemos (probably 74880) and press the reset button on the Wemos?
Pete.
The Following article might help you to understand and fix this issue
You can find the answer here.