FTP 550: access is denied

For the past few days I have had the next issue:
– when i try to delete some files with filezilla or winscp ftp from my azur ftp website, i got 550 access is denied

if i use kudu console i can delete files but when i use ftp client (fileziila or winscp) i still keep those files on azure server even if i deleted them before the kudu console !!

Has anyone seen a similar problem?
Never had this problem in years

Thank you