You can instruct S3Express to automatically retry in case of network error, by setting the global options -retry and -retrywait with the command setopt : www.s3express.com/help/vv_options.html
The option -retry sets the number of retries performed by S3Express in case of a network error. By default S3Express retries 3 times.
The option -retrywait sets the wait time, in seconds, before a retry. The default value is 5 seconds.
If you do not want S3Express to retry on network error, set -retry to 0.