Let's Debug

Test result for ciencias.udc.es using http-01

Error
ciencias.udc.es has an A (IPv4) record (193.144.61.116) but a request to this address over port 80 did not succeed. Your web server must have at least one working IPv4 or IPv6 address.
Get "http://ciencias.udc.es/.well-known/acme-challenge/letsdebug-test": read tcp 172.104.24.29:56094->193.144.61.116:80: read: connection reset by peer

Trace:
@0ms: Making a request to http://ciencias.udc.es/.well-known/acme-challenge/letsdebug-test (using initial IP 193.144.61.116)
@0ms: Dialing 193.144.61.116
@242ms: Experienced error: read tcp 172.104.24.29:56094->193.144.61.116:80: read: connection reset by peer
A test authorization for ciencias.udc.es to the Let's Encrypt staging service has revealed issues that may prevent any certificate for this domain being issued.
193.144.61.116: Fetching http://ciencias.udc.es/.well-known/acme-challenge/OqH_TlHAwXLjcu1nYvbk-HjKcQuwUdE6VIXwUv_SLIQ: Connection reset by peer

Submitted Jun 6 19:12:04 2022. Sat in queue for 3ms. Completed in 8s. Show verbose information.