We have divided redis stack into two seperate apps for redis object cache and redis page cache.
Please do not modify as those settings are needed for it to work
The issue in your case is about socks getting overloaded with too much data, please edit /etc/nginx/conf.d/upstream.conf and remove the word backup after the IP and port, once you have done that,
2. Run nginx -t to confirm that there is no issue with the syntax and then
3. run gp ngx reload to make it work
Ready!