smtp.amx.com.pe has no MX records.
Question and response
Question
dig smtp.amx.com.pe. MX
Answer
The response has no answer records.
Authority
amx.com.pe. 3600 SOA dns1.amx.com.pe. hostmaster.amx.com.pe. 408584073 10800 900 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0