Translation:All our relatives live in Canada.
Both are correct in English... Our relatives all live in Canada, all of our relatives live in Canada.
"All of our" is more common than "all our" in many areas. I feel that "All our" is a shortened version that came out of street use. Both should be accepted though.
Your assumption doesn't pan out though. Looking it up on Google Ngrams, we see that "all our" has always been orders of magnitude more popular than "all of our" but the former has been slowly falling for centuries while the latter has been slowly rising. Until the 2000s when "all our" has suddenly started to regain popularity. The trend is the same for UK and US English too: https://books.google.com/ngrams/graph?content=all+of+our%2Call+ouryear_start=1800year_end=2018corpus=15smoothing=0share=direct_url=t1%3B%2Call%20of%20our%3B%2Cc0%3B.t1%3B%2Call%20our%3B%2Cc0
Both should definitely be accepted of course.