I finally got the HTTP RESTful calls working from the browser.
On the app, pins D0 to D10 as shown as digital PWM pins to attach/ select for buttons. The board manufacturer had specified GPIO 4,12,13 and 14 for relay operation. On the app, by trial and error, I got these pins to be D5, D6, D2, D7. When I use the HTTP calls, the switches respond to D4, D12, D13 and D14 (as per GPIO specified by the manufacturer).
How do use a common spec across these two channels? How can I use GPIO numbers instead of the D0-D10 shown by Blynk app?
I did not go by the printed numbers on the board as I know Dn is used for LEDs.
Eg relay 1 is GPIO4.In the app, D5 is what turns that relay on. In the HTTP call, D4 turns it on!! The second switch is GPIO12. The app does not show digital pins beyond 10. The second relay responds to D12 in the HTTP call.