The OSLC Connect for Windchill CheckInstall, spotted in the First aid diagnosis page, offers a way to automatically verify what's described here below.
When you Associate a CCM project area and Windchill (and it's the same when you Associate a RM project area and Windchill), you may see a No artifact containers available message in the Artifact Containers section, when you should have seen the Windchill product your want your project area to be associated with.
When this error happens, you've to ensure the Windchill user account registred in the OSLC Connect for Windchill has enough rights to see the product.
If you can't access the desired product page, it's certainly because this particular user account has not enough rights. Give this user the rights needed to access the product, or register in the Connector a Windchill user account which has such rights.