"Can Trump cancel the November election?"

No he cannot. BUT....he doesn't need to. Remember how the Supreme Court appointed Gore? Essentially declared him the winner without finishing the re-count.

Trump is angling(in this particular conspiracy theory of mine) to have the results declared null and void due to inconsistencies and fraud involved in the mail in vote. Supreme Court will side with him as always and declare him the winner!

I don't really think he can pull it off but he'll try every dirty trick anybody can think of. And that's what his administration does. They sit around thinking up dirty tricks instead of governing.
Good coffee, good weed, and time on my hands...