Base image pull in Dockerfile fails with 403
Attempting to use a private base image as the
FROM line in a Build Trigger results in a 403 error.
Robot account credentials are required
In order to use a private base image as the
FROM line in a Build Trigger, credentials for a Robot Account with read access to the private image must be specified when setting up the build trigger.
Specifying robot account credentials
A robot account to use to pull the base image can be chosen in the build trigger setup page before the trigger is created: