While upgrading from a version older than 8.19, we would see the below message in the browser because Mesh Sidecar was disabled in the older version:

A fatal error has occurred

The following problem occurred, which prevents Atlassian Bitbucket from starting:

• The system has been configured not to use the Sidecar process for Git operations. Mesh and the Sidecar process are now required and can not be disabled anymore. Remove these properties from 'bitbucket.properties' to continue using the system:
  • mesh.enabled=false
    plugin.bitbucket-git.mesh.sidecar.enabled=false

There's no mention of this message in the Bitbucket logs anywhere. Hence unless Bitbucket is accessible in the browser, we wouldn't know that this is even an issue.

Bitbucket is inaccessible in the browser in situations where:

• In a Kubernetes environment, the livenessProbe or readinessProbe are not disabled, so Bitbucket doesn't even load on the browser
• In an on-prem setup, the proxy is causing issues, and we see a proxy 500 or 503 response code, instead of the Mesh error above.