I can not install 3scale 2.6 on cdk-3.11

I have download cdk-3.11.0-1-minishift-linux-amd64,and execute minishift start successfully

version info is: openshift v3.11.157. And I start to install 3scale,but failed, the my steps is as follows:

minishift ssh

sudo subscription-manager register --username xxx --password  xxx --auto-attach

sudo subscription-manager repos --enable=rhel-7-server-3scale-amp-2.6-rpms,but fail

sudo subscription-manager repos --enable=rhel-7-server-3scale-amp-2-rpms, but too with error:

Error: 'rhel-7-server-3scale-amp-2-rpms' does not match a valid repository ID. Use "subscription-manager repos --list" to see valid repositories.

i refer to

https://access.redhat.com/documentation/en-us/red_hat_3scale_api_management/2.6/html-single/installing_3scale/index 

please help me, Thanks!