@IBK You are correct 
… I hate when people rely on the title for supplying technical details and info, and/or don’t include all relevant details in the initial post anyhow 
@cpcp07 You include the stepper.h library, but I don’t see any actual stepper motor commands in your code.
Steppers rely on constant pulses to get from A to B. Unless this controller has full autonomous control over all that, then you need to provide it in precisely timed code.
I recommend you Google how to use that controller without Blynk first to learn how to make it work.
Be aware, Blynk’s IoT timing and a steppers required timing can often conflict. To work around that I have used dual controllers, one running Blynk that send commands to another running the stepper code.