We have multiple APIs running on AWS instance on different ports. One of the API is giving error "No valid replicaset instance servers found". Other APIs is working fine. No messages in mongodb log. Tried all other options mentioned in stackoverflow such as increasing timeout etc. However did not help.
Same API works properly when run on local server. Restarted AWS instance and it started working fine.
Not able to replicate the issue. Any direction to check the root cause. Would like to avoid happening again. Would appreciate any areas to investigate further to find root cause.