The My Oracle Support Community is an area of the platform that is restricted to users who are associated to a valid Customer Service Identifier (CSI). Access is granted by an organization's Customer User Administrator (CUA), along with one's ability to access the My Oracle Support portal (for knowledge base, service requests, and patch downloads). Check with your company's CUA to make sure you have a valid Oracle account established, and that your account's email address has been associated to a valid CSI.
If you're still not able to log into the My Oracle Support Community after successfully logging in to the My Oracle Support portal, reach out here and we can troubleshoot further.
My Oracle Support Community Administrator