On the previous version of Service Desk Manager, r12.x, when a user logs into Service Desk Manager (SDM), a new Contact will be created automatically if an existing Contact with same user information is inactivated in SDM, however, from r14.1, no Contact is created and the user fails to log into SDM.
an engineer activated her user ID manually.
Release: SDMU0M99000-14.1-Service Desk Manager-Full License
This is working by design. From r14.1, if a user who has an inactivated Contact in Service Desk Manager tries to log into it, a new Contact will not be created automatically. This behavior is not changed if you deinstall the Option "force_unique_userid".
In order to allow the user to log into Service Desk Manager, you need to run pdm_ldap_sync or pdm_ldap_import command to activate the existing inactivated Contact or activate it in SDM web interface manually.