Hi, I am using FreeRTOS verison 8.1.2 and I am facing issue with xTimerIsTimerActive() function. This function always returns pdTRUE even if the timer is not created. What could be the issue?

I'm not sure why you would call xTimerIsTimerActive() without creating a valid timer.

Why don't you initialise your timers and semaphores with NULL, and check for NULL yourself before calling API's that are supposed to work with them?