Can't delete files in sef_adavnce cache

Hello,

I would like to know why I can't delete the files in the sef_advance cache folder by FTP ?

CHMOD 777 on the folder and the files doesn't do the trick.

But when I use the "delete cache" function in the sef advance configuration, the files are well delete.

I mean, this issue only occur with the sef adance folder/files in the cache.
Because I can delete with no problem any files or folder in the joomla cache by FTP, except the sef_advance folder and files.

This issue is not related to my FTP client, because I get the same result with my webFTP in my host account.

Thanks for some explanations

Because it's owned by Apache user. It can depend on server settings. Use JoomlaXplorer or something to delete.