You must activate myCRED error
If you activate the myCRED extension and see an admin alert notice that says " you must activate mycred to use mycred" it means you have not activated the main myCRED plugin and have only activated our myCRED extension. Our myCRED extension integrates Ultimate Member with myCRED plugin which is a plugin by another developer. So to use the myCRED extension you need to also use the myCRED plugin on your site.
Link to myCRED plugin: https://wordpress.org/plugins/mycred/
Once you activate the myCRED plugin (in addition to our extension), the admin notice will disappear.