Hello,
Today I noticed that the daily logwatch contains a lot of FTP authentication failures. We are using a cron job in every 15 minutes which uses SFTP connection. It is 96 connection a day and 96 authentication failure can be found in the sended logwatch email. The cron job working fine (it deletes files so easy to check it).
I did not find errors in the SFTP logs , only this text: [B]no supplemental groups found for user
[/B]How can I repair it and what is it? 
Thank you!