The HTTP verification for the certificate application failed with the error message: "DNS problem: NXDOMAIN looking up A for k4j8s2h.com - check that a DNS record exists for this domain; no valid AAAA records found for k4j8s2h.com."
However, before LE initiated the verification, I could access the HTTP verification file normally from our US server. Why could this be?
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I'm seeing different IP addresses using various services. I think you may have a DNS problem.
k4j8s2h.com. 600 IN CNAME k4j8s2h.com.wcdnga.com.
k4j8s2h.com.wcdnga.com. 60 IN A 61.110.216.74
Request to: k4j8s2h.com/140.150.28.72
This is normal. We use a CDN service, and the IP addresses resolved to in different regions are different. The HTTP-01 verification file is also configured on the CDN server.
I don't think your authoritative DNS servers are returning consistent results for your address records. It appears that sometimes they are missing.
The incorrect glue records shown by dnsviz test above could cause this. See the warning msgs
LE walks the Auth DNS tree and any path it chooses must return correct result
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