No login prompt on Apache

I have an existing Apache server that should allow Kerberos or basic authentication. It should try Kerberos first and then try basic authentication if Kerberos fails. Kerberos still works for domain members, but non-domain members aren't getting the login prompt. For non-domain members, it immediately gives an authentication failed message. It's been months since I tried connecting a non-domain member, but it worked at one time.

Any suggestions on what to try?


Here's a snippet of the config:
<Directory />
Order allow,deny
Allow From 1.2.3.9
Deny From 1.2.3.10
Require valid-user
PasswdFile %%SYSTEM%%
UserID %%CLIENT%%
AuthType KerberosOrBasic
AuthName domain_name_here
ProfileToken On
Options +IncludesNoExec
SetOutputFilter Includes
</Directory>