Issue
Release Phase command consistently fails when I try to deploy a Container Registry & Runtime app to a Private Space. Checking the app logs with the Heroku CLI command heroku logs, I see something like below.
heroku release.1234 - - Error R99 (Platform error) -> Failed to launch the dyno within 60 seconds
Resolution
Please contact Heroku support to have the boot_timeout limit for the app raised to 120 seconds (or more). The error may indicate that the platform hits an internal timeout when starting the one-off dyno to run the Release Phase command. Raising the boot_timeout limit extends the internal timeout.