Asynchronous call back of redis subscriber not called

[Arun210688]

I use Hiredis async feature for my publisher subscriber model.

Scenario :
When I execute PUBSUB CHANNELS from redis-cli , i can see all my 5 channels(channel1 to channel5) list.
When I publish an event to the first channel it will publish to 2nd channel , 2nd channel will publish to 3rd channel and it continues up to 5 channels.

Problem:
Most of the times the set up works fine .
But sometimes the message is received only by the 1st channel and get stuck , the callback of 2nd channel is not getting called . Even if I publish fresh data to channel1 , it is received by channel 1 but not cascaded to channel2
I need to completely restart both redis -server and my application to continue work.

Support needed

Can you help understand why the asynchronous call back of channel2 is not invoked. Is there any debug log messages that I can enable to look into the reason .
What all the possibility for this error scenario.
Is there any methods to check if there are any pending messages for a particular channel in the redis server that are not received by the clients.