diff --git a/maxkey-protocols/maxkey-protocol-cas/src/main/java/org/maxkey/authz/cas/endpoint/CasAuthorizeEndpoint.java b/maxkey-protocols/maxkey-protocol-cas/src/main/java/org/maxkey/authz/cas/endpoint/CasAuthorizeEndpoint.java
index fb12d7e7e..26d76dd1e 100644
--- a/maxkey-protocols/maxkey-protocol-cas/src/main/java/org/maxkey/authz/cas/endpoint/CasAuthorizeEndpoint.java
+++ b/maxkey-protocols/maxkey-protocol-cas/src/main/java/org/maxkey/authz/cas/endpoint/CasAuthorizeEndpoint.java
@@ -150,7 +150,7 @@ public class CasAuthorizeEndpoint  extends CasBaseAuthorizeEndpoint{
 		}
 		
 		if(casDetails.getLogoutType()==LogoutType.BACK_CHANNEL) {
-		    String sessionId = AuthorizationUtils.getPrincipal().getSession().getFormattedId();
+		    String sessionId = AuthorizationUtils.getPrincipal().getSession().getId();
 		    Session session  = sessionManager.get(sessionId);
 		    //set cas ticket as OnlineTicketId
 		    casDetails.setOnlineTicket(ticket);