Additional settings are required for those using Chrome browser to enable cookies.   

Cookies MUST be enabled in the browser for the AppManager website to allow all cookies or to block third-party cookies

• Open Settings in Chrome
• Scroll to the Privacy & Security section and click on "Cookies and other site data"

• Select to "Allow all Cookies"
• Or Select to "Block third-party cookies" in Chrome

• SharePoint root and App manager URLs need to be added