High memcached connections after django upgradation

We recently upgraded our django site from 1.6 to 1.11 which is running on python2. Recently we have observed memcahed down and we have found in error log below message.

[Thu Jul 25 12:56:58.342182 2019] [:error] [pid 32575:tid 140131889002240] ServerDown: error 47 from memcached_get(key): (140131092682816) SERVER HAS FAILED AND IS DISABLED UNTIL TIMED RETRY, host: localhost:11211 -> libmemcached/get.cc:314

I am using memcached default configurations and django default settings. Can any one suggest me fix for this?

And best configurtation for django settings?

Thanks