1) Take a backup of the file: <Self Service Install Directory>\OSOP/PortalExt.Properties file
2) Edit the file and make sure below options are correct:
If not, you can adjust the parameters just for a specific webID. WebID can be obtained from the USS database directly from table: dbo.Company. The column name in that table is webId.
3) Restart CA USS after making the change. The above setting would effectively disable EEM's NTLM authentication option for USS for the tenant-web-id company. It also sets the authentication via screenName (screenName is the default authentication for CA USS)