NagVis Authentication Failed

Hello,
I’ve recently gotten NagVis 1.9 up and running on a CentOS 7 machine, and I’d like to allow authorization besides the built-in admin. I have uncommented these options in the file /etc/httpd/conf.d/nagvis.conf:

AuthName "NagVis Access"
AuthType Basic
AuthUserFile /usr/local/nagios/etc/htpasswd.users
Require valid-user

and these in the file /usr/local/nagvis/etc/nagvis.ini.php:

logonmodule="LogonMixed"
logonenvvar="REMOTE_USER"
logonenvcreateuser="1"

According to the documentation, doing this should enable authorization for Nagios users. Trouble is, it still says Error: Authentication Failed for everyone but the built-in admin user. I would like to be able to have LDAP authentication eventually, but for now I’ll settle for being able to add any users. Any help would be appreciated.
Thank you very much.