we have a site with custom domain datahub.brno.cz which we would like to remove to go back to the default HUB domain oursite-ourorg.hub.arcgis.com. After we remove the domain and hit the save button we get an error instead of the message of successful change. Please see the picture attached. Do you know where could be the problem? We even tried to clone the site so we could set the new domain from scratch but the cloning failed as well.
Thanks a lot for your help.