In any case, please have a look at
https://groups.google.com/g/wildfly/c/jSseTF5TOCQ/m/o1HYOHxABQAJ and try the things suggested there. There are some suggestions, including reaching out to the JIRA admins at Red Hat. If you're able to use the WFLY space normally but just not WFCORE, and the things suggested there don't work, because reaching out to Red Hat please feel free to post back here and we can check whether there is something relevant to your situation in the WFCORE setup. We've not seen that kind of space-specific issue with the migration to Atlassian Cloud though; people have had issues not tied to a particular JIRA space (fka a JIRA project). For those kinds of things the people who follow this group have no powers to resolve things beyond posting info like the thread I linked.