I can't SSH into the manageiq instance on the Google cloud platform

I download the current stable release (Kasparov-1)
https://releases.manageiq.org/manageiq-gce-kasparov-1.tar.gz
I followed the documentation to install manageiq on the Google cloud platform

features
n1-standard-4 (4 CPU virtuales, 15 GB de memoria)
SSH key configured on metadata of the instance
Firewall
default-allow-ssh Entry Apply to all IP Ranges: 10.0.0.0/8 tcp:22

I can’t access to the instance
ssh -i manageiq manageiq@IP-of-the-instance
Permission denied (publickey,gssapi-keyex,gssapi-with-mic).

Note: I can access all instances GCE of my project through VPN