Do you have Kaspersky or other antivirus software installed? Or perhaps a Chrome add on that may be blocking the editor from loading? Many are reporting that Kaspersky is blocking the Tinkercad editor from loading.
The responsible Kaspersky component for this is the Web Anti-Virus and Network
Settings that can be found under Protection and Additional tab. You may need to allow www.tinkercad.com in this tab.
Disable Kaspersky blocking loading of designs:
1) Open Kaspersky total security
2) Open Additional settings
3) Open Network settings
4) Scroll down and find Manage Exclusions open it
5) Select the Add button
6) put this in the domain box www.tinkercad.com/
7) Make sure Active is selected and click ADD button
8) close by clicking the x on all open Kaspersky windows