FNDFS or the Report Review Agent (RRA) is the default text viewer within Oracle Applications, which allows users to view report output and log files. Report Review Agent is also referred to by the executable FNDFS. The default viewer must be configured correctly before external editors or browsers are used for viewing requests.

FNDSM is the Service manager. FNDSM is executable & core component in GSM ( Generic Service Management Framework ). You start FNDSM services via APPS listener on all Nodes in Application Tier.

There are certain scenario  where we can't see the output of Concurrent Requests. It  just gives an error.

Then check the fndwrr.exe size in production and compare it with  Test Instance.

fndwrr.exe is present in  $FND_TOP/bin

If there is any difference then relink the FNDFS executable.It might not be in sync with the binaries.

Command for relinking
adrelink.sh force=y "fnd FNDFS"

Ensure that you have the necessary permissions to use these commands, especially if you are making changes to production environments.

You may need to set the environment variables specific to your Oracle EBS instance before using these commands. This can be done by sourcing the appropriate environment file.