Hello,
My project is using Max485 to read holding register of a device and I got it done but when I am trying to show the data on Blynk App the code does not work I think it because Blynk library using the same RX/TX that modbus used at the same time so is there a way to stop Blynk library from using the RX/TX or is there any way to solve this issue.
Please let me now if you want me to provide you any further information.
In every Blynk example you will find these two lines:
/* Comment this out to disable prints and save space */
#define BLYNK_PRINT Serial
the define obviously points to serial port used by Blynk
I have used Modbus RTU, RS485 and BLYNK_PRINT Serial at the same time ons ESP8266 I don’t belive this is the problem.
Do you have more info about
And all this on a SINGLE serial port?? 
Yes, BUT I was reading Modbus inside a timer every X seconds.
When it tries to read registers and send data to Serial it may cause some unsuccessful readings only. And that is why I believe this has nothing to do with the fact his project doesn’t work with Blynk, and unless we get more details from the error or why it’s not working it’s really hard to tell.