Cannot log out of RT

I have RT set up to do authentication through apache which uses Kerberos.
It works fine and logs me in as username@KRBTEST
The problem is that when I click on logout, I get the screen that says: You
have been logged out of RT, but then seems to immediately re-logs me in and
I go back to my home page.
Here is the code that maybe needed for assistance:

Apache Kerberos configuration

    AuthType KerberosV5
    AuthName "Please use the GR login and password"
    KrbMethodK5Passwd on
    KrbMethodNegotiate off
    KrbServiceName HTTP/rt.mel.nist.gov@KRBTEST
    Krb5Keytab /etc/httpd/conf/krb5/http.rt.krb5.keytab
    Require valid-user

RT_Site_Config

Set($WebExternalAuto, 1);
Set($WebExternalAuth, 1);
Set($AutoLogoff, 60);
Set($WebFallbackToInternalAuth, 1);

Thanks for your help

Janet Bass
Unix System Administration
Manufacturing Engineering Laboratory
304/Room 12
100 Bureau Dr
Mailstop 8203
Gaithersburg, MD 20899-8203
EMAIL: jbass@nist.gov
PHONE: 301-975-8425

I have RT set up to do authentication through apache which uses Kerberos.
It works fine and logs me in as username@KRBTEST
The problem is that when I click on logout, I get the screen that says: You have been logged
out of RT, but then seems to immediately re-logs me in and I go back to my home page.
Here is the code that maybe needed for assistance:

This auth is handled by Apache and your browser, not RT, so RT cannot log you out.

Since you have WebFallbackToInternalAuth set to 1, RT shows the Logout
link, since you might have logged in using internal auth.

-kevin