SAM proxy thumbslug katello

Hi,

I use SAM to register VM
I want to use the SAM as a proxy to update the VM. (cdn access)
How should I configure thumbslug.conf and katello.yml?
To date, this does not work, I get an error 502 in the access log thumbslug. it can not find repomd.xml. The proxy does not operate. (port 8088)

Actually i use local repository to update. I think the security updates are not ok .... That's why I want to test with an access to cdn via the proxy SAM (Candlepin)

Someone managed to run SAM as a proxy ?

Thanks.