Obtain the credentials to access the Marketplace Demo instance
You should have already received the credentials after submitting a request to start selling your plugin. Please check your inbox for an email titled “You have been granted access to the JetBrains Marketplace Sandbox".
You need your credentials to access both the Marketplace Demo server and the Sales Systems Marketplace Demo. You will need to provide your credentials separately for both of these applications (it is normal if you are asked to re-provide your credentials when going from the plugins repository to the shop.)