CE10 - internal error - secLdap plugin

[travis2005]

After installing the CE10 SDK on our IIS Server my (web application) .NET program generates a CR report but only about 50% of the time - for the other 50% of the time I get the error (which occurs when the program attempts to logon to the CE10 server) :-

"An internal error has occurred in the secLdap plugin."

Our templates reside on a CE10 server. Another server contains our SDK and the code (that calls the API and loads the templates from the CE10 server). Has anyone received this before or does anyone have any ideas ?

My code to logon is as follows :-

SessionMgr ceSessionmgr = null;
EnterpriseSession ceSession;
Response.Expires = 0;
ceSessionmgr = new SessionMgr();
//Get username
user = Request.ServerVariables.Get("HTTP_PROXY_REMOTE_USER");
//Get password/token
password = Request.ServerVariables.Get("HTTP_LDAPTOKEN");
apsName = "NYITDCED001";
string apsAuthType = "secLDAP";
ceSession = ceSessionmgr.Logon(user, password, apsName, apsAuthType);

ceSessionmgr.Dispose();
ceSessionmgr = null;
ceSession.Logoff();
ceSession.Dispose();
ceSession = null;
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