AP & Go for H1b Stamping in Canada

[wheretogo]

I got PR for Canada. I have to enter for one time to get PR for canada. I have AP. My H1B Restamping rejected from St. Louis on 221g.

My question :

1> Can I go for H1b Stamping in Canada while going for PR ?
2> If they stop for any reason for H1b Stamping , Can I come back on AP.
3> What is chance not to get H1b Stamp in Canada. I am USA last 3 years.

Thanks,