Trouble Shooting Tips
If login failed for a correct 'UserName' and 'Password',
Check if the User is imported from 'Active Directory'.
If User is not imported from Active Directory, then submit only the username and password to http://machinename:portname/servlets/RequestServlet for Authentication.
If User is imported from Active Directory, then submit the username and password along with DOMAIN_NAME and logonDomainName to http://machinename:portname/servlets/RequestServlet for Authentication.
DOMAIN_NAME represents the Domain to which the User belongs, logonDomainName represents Authentication Mode,
Local Authentication or empty value refers to Local Authentication mode, and AD_AUTH refers to Active Directory Authentication Mode.