Just to clarify, After you register for a trial with an account that already has a standard or cloud license, you need to click the Switch to trial of Universal edition on the Account Management window on SnapDevelop IDE.
Plus: make sure you haven't already logged SnapDevelop in with the same account on another machine. If you did, please log out your account from the other machine or contact your license admin to log your license out from Appeon's website.
Note: You can't use your paid license and trial license on different machines at the same time.
If you still get any issue, please report a bug at https://www.appeon.com/standardsupport/newbug with a screenshot of the SD Account Management window.