Hi Stephan

Thanks for posting in the community. If you recently upgraded I would recommend logging in using a private or incognito window as this can sometimes be a browser related issue. If that resolves the issue I'd recommend clearing your cache and cookies. After that you should be able to use a normal browser window. If that doesn't work could you please reach out via support@lucidchart.com so we can take a closer look at what's going on?