Problem with MFT to upload document

Hello,

Last week, we used the MFT server to send and receive documents without problems

Today, we trying to send documents via the MFT and we get this message on the interface : "The file or directory you're trying to access is not available to you."

When I'm reading the log files, I have this error code : 

• SESS_FILE_SHARE_DISABLED
• HTTP_OKAY (200): SESS_FILE_SHARE_DISABLED
• HTTP_OKAY (200): SESS_PERMISSION_DENIED

How can i solve this problem ?

Thanks