When I mentioned exporting, I meant are you exporting your file as a "Scirra Arcade"?
Unfortunately some third party plugins are also not allowed in the scirra arcade.
If you check this link:
The link above shows the plugins that are supportive. In this case, it doesn't show that the canvas is supportive, so that probably explains the problem your having. If you really want to show off your work there are other hosting sites like Kongregate or Newgrounds where third party plugins will work, the only problem being that people are a bit more picky on those sites as they expect a full game with graphic arts and such to be finished.
Clay.io is another great site to host games, so check it out as well. The community is also pretty good.