mailserver.servidoraweb.net has no SRV records.
Question and response
Question
dig mailserver.servidoraweb.net. SRV
Answer
The response has no answer records.
Authority
mailserver.servidoraweb.net. 86400 SOA nut1.nuthost.com. servers.servidoraweb.com. 2022040805 86400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0