Permissions required scale up environment composer 2?

Question

I already have an environment running, but want to scale up the machine sizes. But keep getting a very similar error to this:

    UPDATE operation on this environment failed 3 minutes ago with the
following error message:
Composer Backend timed out. Currently running tasks are [stage:
CP_COMPOSER_AGENT_RUNNING
description: "No agent response published."
response_timestamp {
  seconds: 1618203503
  nanos: 291000000
}
].

The gcp docs say that the service account doesn't have required permissions. I check required permissions also in the docs. My personal account and service already have the role Environment and Storage Object Administrator. And the service account already has the role Cloud Composer v2 API Service Agent Extension. I don't understand which permission am I missing.

Service account that the composer uses has roles:

Cloud Composer v2 API Service Agent Extension
Editor
Environment and Storage Object Administrator
Service Account User

And my personal account has roles:

Editor
Environment and Storage Object Administrator
Service Account User
Storage Admin
Viewer