Blynk.setProperty() command not changing button color

Pete, thanks for the tip!

because the BLYNK_WRITE function is called on an interrupt? if so, then the variables that are declared outside of this function must be with the “volatile” modifier?

No.

It’s difficult to make any sense of the code snippets that you’ve posted, or comments such as…

Pete.

Sorry for the confusing story, but nevertheless, after adding ‘volatile’ before the global variable, the code began to work correctly! Post all the code?

WORKED!

thank you all, the problem was found, the IDs were mixed up, i.e. I wrote the properties to the wrong virtual pin!