I'm getting "ERR max number of clients reached" for my Redis, how can I avoid this?

Resolution

There are several things you can do to avoid this, such as using a connection pooler to reduce the number of connections, setting an appropriate connection timeout to close inappropriate idle connections.
Here is a blog post, talking about above things, and also many useful tips. Please check it out!
https://blog.heroku.com/real-world-redis-tips