I had this issue a week ago: Make sure the domain you want to add is a primary domain or an alias of a primary domain. GAE does not support mapping to a secondary domain.
If you map to an alias domain note that you will not be able to send mails with an admin sender from this domain. (Ex: if you want to send emails from no-re...@my-alias-domain.com) -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-appengine/-/GcX65VUghcYJ. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
