Nothing appears in the atlassian-confluence.log file
No startup messages or any content appears in the atlassian-confluence.log, usually during an upgrade attempt, restart, or some other configuration change.
Check the permissions on both the confluence-home and confluence-install directories. On a Linux system, use "ls -al".
Permissions are insufficient for the user who is running Confluence to write to the confluence-home directory.
Apply the appropriate ownership or permissions to the confluence home directory. Something similar to:
chown -R confluenceuser:confluenceuser confluence-home
substitute 'confluenceuser' with the name of the correct user, and 'confluence-home' with the name of your home directory.