The Ottomatic Backups link only shows up for servers added to the Ottomatic Console by Ottomatic. Servers that you’ve added manually as on-prem servers (even if its actually an Ottomatic server that you somehow got around the duplicate url check) will not give you the options to view the credentials, view backups, and other options specific to Ottomatic servers.
You should be able to tell which ones were added as on-prem servers by the icon in the server header or in the first column of the servers table.