You may need to reauthenticate your connection to RDA, and might not be sure what your Sage account email address is.

Finding your Sage account

1. Open Sage 50 Accounts.
2. On the Company Selection window, highlight your company.
3. Check the Sage account column. This is the address you logged in with. 
   
4. If you're prompted to login to your Sage account, use the email address shown here.