Redis: connection pool timeout (code: 2)

Hi friends,
I have lunched multiple network servers, multiple application servers on single machine. after some weeks, I see below error when I want to see a gateway data:

I am having the same problem. Any luck figuring out a solution?

A timeout occurs when the client is unable to connect within a reasonable amount of time to the (Redis) server. Either Redis is unable to respond to the request or there is a network issue causing the connection to fail.