Hi @amit_singh
You can enable debug printing by following what was done in this thread, but I don’t really recommend it.
That is a big hammer for debugging the internals of the Spark code.
You should probably just add your own Serial.print() statements in your code instead.
Another option is to use the Spark.publish() function to send debug messages to the cloud periodically (once per second max rate allowed with a burst of upto 4).