Hello. I was able to verify a domain previously on a separate Tenant, but realized quickly we’d just need a separate new tenant. However, even after removing that custom domain in the original tenant, I am still unable to verify the original domain again. I have tested with many different custom domains, including the same one just without the plural (s) at the end. The CNAME shows record shows up properly in MXTOOLBOX as well. If additional information is needed, such as the exact name of the domain, I can provide it (not sure if it is secure here).
After removing the domain from the original tenant, it might take some time for the changes to synchronize across Microsoft services. Wait at least an hour and then try to verify the domain again. DNS records need to propagate before Azure AD can successfully verify the domain. Official Website Go back to your domain registrar’s site and verify that the DNS entry matches the information provided by Azure AD. If you can’t update the record on the registrar site, share the entry with someone who has permissions to add the entry and verify its correctness.