I used the Migration Assistant to migrate one space to our cloud trial site. Migration Assistant said it completed successfully, but when I look at the cloud trial site, the migrated site is not found.
I'm the admin for the cloud demo site. I can't see any other spaces as I've only migrated a site that wasn't used in production.
Can you try going to this: YOURBASEURL.atlassian.net/wiki/spaces/spacepermissions.action?key=YOURSPACEKEY
Did you try navigating to global space permissions to check if the space is listed there?
yourwikisite.atlassian.net/wiki/admin/permissions/viewdefaultspacepermissions.action
Kind Regards
Utkarsh