I have been using let's encrypt SSL certificates with GoDaddy for some time, using DNS verification.
This stopped working. It appeared that _acme-challenge txt records were not returned.
It turned out that the records were entered with the wrong hostnames due to an API change.
And the GUI displayed them in a confusing fashion.
Go to Solution.
This turned out to be a false alarm. Almost.
Undocumented API changes caused this problem. The PUT command now requires an array in JSON, even when only a single element is provided. This was not formerly the case.
Also, the PUT command now requires a domain-relative name; Formerly it did not.