Thanks for the reply. I should have mentioned that if i run the command line without the -t option, a scan is done of the login page so it seems that the target is accessible.
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<configuration>
  <context>
    <name>Default Context</name>
    <desc/>
    <inscope>true</inscope>
    <tech>
      <include>Db</include>
      <include>Db.CouchDB</include>
      <include>Db.Firebird</include>
      <include>Db.HypersonicSQL</include>
      <include>Db.IBM DB2</include>
      <include>Db.Microsoft Access</include>
      <include>Db.Microsoft SQL Server</include>
      <include>Db.MongoDB</include>
      <include>Db.MySQL</include>
      <include>Db.Oracle</include>
      <include>Db.PostgreSQL</include>
      <include>Db.SAP MaxDB</include>
      <include>Db.SQLite</include>
      <include>Db.Sybase</include>
      <include>Language</include>
      <include>Language.ASP</include>
      <include>Language.C</include>
      <include>Language.JSP/Servlet</include>
      <include>Language.Java</include>
      <include>Language.JavaScript</include>
      <include>Language.PHP</include>
      <include>Language.Python</include>
      <include>Language.Ruby</include>
      <include>Language.XML</include>
      <include>OS</include>
      <include>OS.Linux</include>
      <include>OS.MacOS</include>
      <include>OS.Windows</include>
      <include>SCM</include>
      <include>SCM.Git</include>
      <include>SCM.SVN</include>
      <include>WS</include>
      <include>WS.Apache</include>
      <include>WS.IIS</include>
      <include>WS.Tomcat</include>
    </tech>
    <urlparser>
      <class>org.zaproxy.zap.model.StandardParameterParser</class>
      <config>{"kvps":"&","kvs":"=","struct":[]}</config>
    </urlparser>
    <postparser>
      <class>org.zaproxy.zap.model.StandardParameterParser</class>
      <config>{"kvps":"&","kvs":"=","struct":[]}</config>
    </postparser>
    <authentication>
      <type>2</type>
      <strategy>EACH_RESP</strategy>
      <pollurl/>
      <polldata/>
      <pollheaders/>
      <pollfreq>60</pollfreq>