The Marketing Automation Operations server requires access to the configured xConnect model that is provided by the xConnect collection role. When deploying a Marketing Automation Operations server, you must enable the collection role on the server to provide this required service.
To enable the collection role on the server, rename the \App_data\Config\sitecore\Collection\sc.XConnect.Collection.Initialize.xml.disabled file by removing the .disabled extension.
The resulting file name is:
sc.XConnect.Collection.Initialize.xml
.