Hi Duy,
In order to host external urls in a SG URL Widget, the source media must allow itself to be embedded in an iFrame. You’d need to talk to the Tableau folks about if they’re denying iFrame embedding or not. If you’re hosting your graphs locally or on a server where you have control over embedding options (at the Apache or nginx level: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options), you’ll probably get more mileage that way. I hope this helps!