Hi,
The others users are public users visiting your site?
If so, could you please check if you did not add following code into your web.config file?
<location path="">
<system.web>
<authorization>
<deny users="?"/>
</authorization>
</system.web>
</location>
With the above settings all users would be prompted to authorize before visiting the live site.
Please take a look in
this section of Devguide for more information.
Best regards,
Ivana Tomanickova