I found the issue and wanted to post in case someone else runs into this. After looking up the error in the log file “SessionNotAvailableException” it lead me to wrong permissions on the php sessions folder. When php was updated it reset the permissions on the session folder which in CentOS 7 is located at: /var/lib/php/session. By default the permission was root:apache so I changed it root:nginx. This solved the issue and owncloud is back in operation.
Adam