Not able to register MS Active Directory user in Portal UI

Products

• CA API Developer Portal

Issue/Introduction

Registering an LDAP user but its not working properly.
Getting following error in, 
portal_authenticator_log

[ERROR] [a.b.C.d.e.f.LDAPImpl] [VALUE1] [IDVALUE] [||Layer7-SecureSpan-Gateway/v9.4.00-b9807|] Missing Required User Attribute: Surname, Portal Attribute LAST_NAME_ATTRIBUTE
And then stack below,
portal_authenticator.0.somevalue@somevalue    | com.ca.apim.exception.BaseException: Missing required user attribute 'Surname' in Identity provider

Environment

Release : 4.4

Component : API PORTAL

Resolution

It doesnt get enough details to properly map a user within the portal.
The AD providers incorrect attributes were the cause of the issue. Check the AD users surname and last_name_attributes in the actual provider.