Ran into this issue after modifying Interspire Shopping Cart’s main .htaccess file to 301 redirect non-www urls to www.domain.com . A log in to the admin section would fail each time, but using the same password after removing the www redirect would work. The problem is in the shop path variable, it must include the www part of the domain name. There are two points that this can be fixed in, by either editing the spop path under store settings, or by modifying the config.php file in the line that specifies the ISC_CFG variable “ShopPath”.