Make sure you are connected to the correct cloud account.
Check the account number in the browser link address that you are trying to open. If you used a different account or a trial one, your browser might still remember it.
Check your email inbox for the Language Cloud invitation email and open it. If you are unable to find it then ask the person who invited you to resend the email.
If the issue persists,
clear your browser cache. If you are still having trouble, then
log a Support Case in RWS Support Gateway.