I am getting the error “Internal error: filemng failed: Unable to logon user “while accessing the File Manager option in plesk control panel

Solution :

If you are trying to connect ftp using wrong username and password multiple times then your ftp username will be locked in server.

In order to resolve this issue you have to check and unlock the ftp user in server. If you want to unlock the FTP user kindly raise a ticket in our support area