Hi,
It seems that there isn't enough resources available in that zone for you VM request.
To address the issue you can try to create that instance in a different zone, for example us-west1-a; or try to create that instance in a different time/day.
Note that the recommendation is to spread your workload across different zones to reduce the impact of these issues on your workload,
reference. There is also a feature called reservations that provide a very high level of assurance in obtaining capacity for Compute Engine zonal resources,
reference.