Hm looks like you’ve hit an old/niche Influx bug: error parsing query: unable to find time zone · Issue #10196 · influxdata/influxdb · GitHub. Maybe you’re using an outdated Influx version?
(also “America/Montreal” is a deprecated time zone, so that first error is to be expected)
If you can’t get the tz() clause to work, you can also add an offset to the GROUP BY time() clause - see Explore data using InfluxQL | InfluxDB OSS v1 Documentation. It’s a bit more “manual”, but should yield the same result.