"Image not found on registry" error when upgrading from CE to BE or self-updating on Synology NAS

Affected versions: 2.17.0 and above

Issue Description

When running an in-app upgrade within Portainer that is running on a Synology NAS, users may receive an error "Image not found on registry".

Cause

Our team is currently investigating the cause of this issue, but we suspect this is a consequence of Synology's custom Docker build.

Workaround

The workaround for this is to follow the legacy upgrade steps found in the Portainer documentation and follow the manual steps option for your environment. This will guide you through the steps to update your Portainer install.

Some users have also reported success with manually pulling the missing image first, then attempting the in-app upgrade.

You can find more details on this issue in the GitHub Issue.