Kee Vault version 1 (the web app) is designed to store all of your passwords on your local machine for improved security and reliable offline access that can’t be matched by other web-accessible password managers.
Your web browser’s “Private browsing” mode is designed to prevent web apps from storing information on your local computer and therefore prevents Kee Vault from functioning.
To use https://keevault.pm, ensure that Private Browsing mode is disabled.