Once installed you need to go to CB > Plugin Management and ensure the plugin is published and public. Next be sure to follow the instructions found below very carefully.
www.joomlapolis.com/forum/6-news-and-publicity/229505-configuring-cb-connect-7x
A not found error is typically a Joomla menu item permission issue. Find your CB menu item with the "cb-profile" alias and ensure it's public and published. You can also create a public and published Joomla menu item for the menu type Community Builder > Type and select CB Connect for the plugin to ensure CB Connect can be reached.
Enable debug mode and maximum error reporting in Joomla global configuration to ensure errors can output during testing.
If issue persists after trying the above please PM backend super administrator login credentials and will take a look.