ciencias.udc.es has an A (IPv4) record (126.96.36.199) 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 188.8.131.52:56094->184.108.40.206:80: read: connection reset by peer
@0ms: Making a request to http://ciencias.udc.es/.well-known/acme-challenge/letsdebug-test (using initial IP 220.127.116.11)
@0ms: Dialing 18.104.22.168
@242ms: Experienced error: read tcp 22.214.171.124:56094->126.96.36.199:80: 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.
188.8.131.52: Fetching http://ciencias.udc.es/.well-known/acme-challenge/OqH_TlHAwXLjcu1nYvbk-HjKcQuwUdE6VIXwUv_SLIQ: Connection reset by peer