mail.bancoguayaquil.com has no MX records.
Question and response
Question
dig mail.bancoguayaquil.com. MX
Answer
The response has no answer records.
Authority
bancoguayaquil.com. 86400 SOA . . 830 900 600 432000 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0