mx-hdc.mailgrid.com.br has no TXT records.
Question and response
Question
dig mx-hdc.mailgrid.com.br. TXT
Answer
The response has no answer records.
Authority
mailgrid.com.br. 900 SOA ns-889.awsdns-47.net. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0