Second domain verification support needed

Hi,
We have verified one of our domain addresses. But the other one we use for call back (for back end) is not working. We used Add a tag to your domain’s page and it still doesnt work. Please help.

Hello,

Thank you for reaching out in relation to Our Domain Validation process, the next steps will be sent to you via DM. Please refer to our domain validation resource: Domain Validation Explanation for any further questions you may have about the process.

Thank you.