Comment 1 for bug 1823096

Might this be a limit based on your account?

I was able to bootstrap to "australiaeast" without issue.

Juju has default controller constraints for memory (3.5GiB on Azure), but any specification of constraints for "instance-type", "mem", "cores" or "cpu-power" will override it.

If you know the instance type you want to use, you can supply:
"--bootstrap-constraints instance-type=<type>"

Or you can specify a lower memory constraint with:
"--bootstrap-constraints mem=1024M"

I will mark this as incomplete for now; we can re-open if further info is added to indicate a bug.