Please try troubleshooting this issue with the Chrome browser. We recommend using the Chrome browser with Tinkercad.
Does the issue persist in the Chrome browsers? If so, your WebGl support in can get turned off if you have a certain hardware configuration, such as an older graphics card or unsupported Operating System.
In this case, please try the following steps?:
1. Copy/Paste this URL in your browser: Chrome://flags
2. Enable the entry: "Override software rendering list", as seen below
3. Click "Relaunch Now" at the bottom of the page to relaunch Chrome with this setting.
Then see if Tinkercad is working for you? If not, please reopen this ticket.
You might also try: In chrome://settings: "Use hardware acceleration when available"