Every evening I run a script in AIX production box, which executes below command:
rcp prod_bkup.tar prodapp@IP:/data/appl/prod

This will rcp a backup of around 11 GB from production to another machine (runs every evening so overwrites previous one). Just to keep the backup safe. Since 2-3 days, I notice that this command takes quite longer than normal days and when I go to another machine - I am allowed to login, But when I give 'ls -l /data/appl/prod' nothing comes and looks like session on both windows kinda hung state. Then I press ctrl C on production.

Then next morning 'ls -l /data/appl/prod' command also works fine on another machine and I see that backup is copied (not fully, the byte difference is there) of around 2 hours later time stamp. And I tried rcping a 0 byte from production to another machine also works fine. Only problem comes during evening when I rcp the backup.

Do you know what might be going wrong and where can I find such logs on AIX machines?

Please advice / Thank you.