heartbeat ticks are stopped even if kws.is_connected() is true

Greetings fellow developers,
I am logging ticks by below method but ticks are getting stop rarely, I am logging at every ticks and checking kws.is_connected() every minute.
##code
def on_ticks(ws, ticks):
global count2
print(count2, "tick") ## stops randomly
ticks_queue.put(ticks) # sending ticks for further processing
count2 += 1
##code
while flag1:
print(datetime.datetime.now(),": RUNNING", connections[0].is_connected())
sleep(60)
##code