We have two separate tenants for DEV and PROD. I configured separate DEV and PROD Custom domains and also Created DNS entry with correct CNAME. nslookup shows correct entries for both the domains.
Dev domain seems to work fine but PROD domain fails verification.
Please let me know if you need domain specific details to take a look.
I have just checked your Dev and Prod tenants and see the same observations as you.
It seems like your Prod tenant’s custom domain is still in the pending verification status.
I have checked your custom domain’s DNS record and see the correct CNAME value as well. In this case, please allow some time to pass before checking back to verify it’s status.
I recommend referring to the FAQ below for additional guidance: