Oki C5550 MFP User Manual page 60

On the other hand, if the HTTP server does not allow an
anonymous account for authentication of connection to the web
page, the user will be prompted to enter a user name and
password first when connecting to the web site. In this mode, the
file saving feature is available only when entering the user name
and password permitted by the server in the Login name and
Password field for the MFP.
Therefore, make sure of the mode that your Web Server allows
before using HTTP for file saving. If anonymous access mode is
not allowed, you must have a legal HTTP account and password.
Since this MFP will check whether the directory for file saving
really exists before proceeding to file saving and writing after
scanning to the specified directory, you have to set the directory
for files saving as "browse" and allow for writing in the Web
Server; otherwise the MFP will not be able to write the file into
the directory.
If you wish to use the MFP to save files, in addition to making
some settings in Web Server, you will have to confirm that the
account has writing privilege for connecting to the Web Server. If
not, the MFP will not be able to "write" the scanned file in the file
system.
C5550 MFP User's Guide
Configuring your machine > 60