This problem can occur upon initial installation, or after an upgrades (if you deleted the contents of your /usr/local/haast/web_interface directory), and you have configured Apache to require a password when browsing the (virtual) directory. The problem is that your password file was not created (or was deleted during your upgrade). Please review section for 3.4.5 for details, but in summary you can create the
missing password file as follows:
htpasswd -c /usr/local/haast/web_interface/.htpasswd user1
which will also prompt you for a password for the newly created user account named ‘user1’.