Temporary failure in name resolution, Failed to open redis DB connection

Question

I hope this message finds you well. We have encountered an issue with our Point of Sale (POS) application running on AWS EC2 instances. Specifically, a restaurant attempted to add an order to the sale_master table in the database, and an error occurred with the following message:
"Failed to open Redis DB connection 
"Temporary failure in name resolution"

This error occurs once in a blue moon. But I want to resolve it. 
I checked DNS configuration. Checked Ports which are enabled. 
I checked the DNS settings in the file that /etc/resolv.conf is pointing
I don't know what are the other reasons.

Answer

This issue can occur when there is no connection to the database or when the connection is too slow / experiencing increased latency. Are your POS devices reaching the EC2 instance over a cellular network (LTE or 5G)? If so this could be causing the DNS resolution to fail. Try correlating the error with other data points like latency spikes on your connection, or DB IP address changes / cached DNS records.

Temporary failure in name resolution, Failed to open redis DB connection

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