Thanks !
Reason is that these 3 passwords were identical
Web Interface -> Storage Management -> Your storage node -> Management Username & Management Password
Web Interface -> FOG Configuration -> FOG Settings -> TFTP Server -> FOG_TFTP_FTP_USERNAME & FOG_TFTP_FTP_PASSWORD
/opt/fog/.fogsettings -> storageftpuser & storageftppass
But not the local ‘fog’ user’s password on the Linux FOG server
It works like that on previous installation, this time I changed the 3 others passwords to match with local fog user and everything is fine 😉