UPDATE: Now resolved by updating the DNS txt file, it is worth noting that it is not clear if the validation process is both DNS and HTML file or one or the other, nevertheless, its now sorted.
We recently moved servers and received an email with the following message;
We're no longer able to verify one of your organization's domains: #######
The file is present on the server and assessable via www.domain.com however, we can still not get it validated.
Any tips are greatly appreciated