If you’ve recently upgraded your QNAP NAS to firmware version 4.3.3 and have some of your pages in your internal web share password protected using a .htaccess file you may have discovered it’s stop working. I had the same problem with .htaccess and logged a support ticket, but i ended up resolving it myself.
After following the instructions in this article to get the logs going: http://technedigitale.com/archives/407
I discovered authgroupfile for whatever reason is no longer working
I removed the line, as it was set to null anyway in my .htaccess file
and now it is once again seeing my .htpasswd file and accepting the user and password.
A feature request to get this module re-enabled by default has been made, please support it by raising a support ticket via the helpdesk app on your QNAP and quoting ‘Mantis BT ID 19859: [4.3.3.0173 and before] Web Server Service: Add authz_groupfile_module modules/mod_authz_groupfile.so to Default Configuration.