Failed to load at least one of the configuration entries for the package. Check configuration entries for "Configuration 1" and previous warnings to see descriptions of which configuration failed.

This is not an issue, if configuration files are attached to the Job from configuration tab. The message says that, Package is not able to load the associated config files which was enabled during the design time. While deploying the package to servers, we need to remove the attached config files, to avoid this error message.