Our Cloudflare DNS expert left the company and I’m trying to fill in so pardon my lack of knowledge.
We are working with a marketing vendor for some email communications. They are trying to get our domain registered to their Mailgun account. When they try to send an authentication link they receive a message “It looks like your domain is already connected to a Mailgun, The service we use to send email on your behalf. Unfortunately, this means that we won’t be able to verify your domain.”
I looked in our DNS records and I do not see any Mailgun MX or TXT records. I opened a ticket with Mailgun support to try and find out which Mailgun account has our domain but they would not share that information. I opened a ticket with Cloudflare support but have not received any reply.
Does anyone have any ideas on how to find which Mailgun account has our domain on their account?
I’m sympathetic to your situation. Unfortunately there really isn’t anything that the Cloudflare Community, or Cloudflare support can offer in the way of assistance with a third-party product like Mailgun. While I am sure it is frustrating for you that Mailgun cannot share the details of what account has your domain connected to it, there are security and privacy issues in play there.
I have Mailgun configured on numerous domains, and I’ve never seen an invitation that involves a link. I don’t doubt your claim. I’m just unfamiliar with that process of adding a domain to Mailgun. Mailgun doesn’t use any TXT record verification. They just have you add the required SPF and DKIM records. If you weren’t using a dedicated subdomain for your Mailgun, this becomes more difficult to keep track of, especially if you don’t know which of your DKIM selectors are used for specific services.
There is a relevant article in the Mailgun KB that addresses your situation, however, without any knowledge of whose Mailgun account holds your domain, it will prove difficult to complete the required steps. It might be worth reviewing any services that you engaged with in the past that may have used Mailgun. At lest then you can work from a shorter list than you currently are. You could also consider creating a dedicated subdomain for your marketing campaign, which is good practice anyway.