The validation request to this domain was blocked by what is likely a Palto Alto web application firewall device. The 'acme-protocol' application needs to be permitted on the firewall in order for the request to succeed. See https://community.letsencrypt.org/t/177600 for more information.
The server at 160.129.198.244 produced this result.
Requests made to the domain
Request to: neuroxy.langneurosci.org/160.129.198.244, Result: [Address=160.129.198.244,Address Type=IPv4,Server=,HTTP Status=503], Issue:
Trace:
@0ms: Making a request to http://neuroxy.langneurosci.org/.well-known/acme-challenge/letsdebug-test (using initial IP 160.129.198.244)
@0ms: Dialing 160.129.198.244
@55ms: Server response: HTTP 503 Service Unavailable
A and AAAA records found for this domain
neuroxy.langneurosci.org. 0 IN A 160.129.198.244
Challenge update failures for neuroxy.langneurosci.org in order https://acme-staging-v02.api.letsencrypt.org/acme/order/5751349/2674989104
acme: error code 403 "urn:ietf:params:acme:error:unauthorized": 160.129.198.244: Invalid response from http://neuroxy.langneurosci.org/.well-known/acme-challenge/UUZvyDgShqLUEs98srF3jRlrrVmfyV8jpqQ0Enp48To: 503
The IANA public suffix is the TLD of the Registered Domain
The TLD for neuroxy.langneurosci.org is: org
The current status.io status for Let's Encrypt
Operational