Please ensure that the LogicMelon plugin installed in your RDB database is up to date by finding it in the RDB Store (Under the plugins tab RDB Store); if it says Installed then it is up to date, otherwise, the button will say Update.
Check and correct as appropriate (with LogicMelon's direct help if necessary) the settings in the LogicMelon plugin, accessible via:
Click Options then click Plugin Packages.
Search for and select the Logic Melon plugin.
Click Options then click Accounts.
Update the required credentials.
If this still does not work please contact Logic Melon as they manage these accounts/credentials.