You have used reserved domain name in default link type URI. Please choose different domain.
Explanation
You have used reserved domain name in default link type URI, this reserved domain name includes 'open-services.net', 'purl.org', 'jazz.net' and 'xmlns.com'.
User response
Please update default link type URI and ensure you have not used reserved domain name. Alternatively you can delete the default link type URI and click 'Suggest' while 'Apply'/'Publish', it will suggest valid default link type URI.