When you send an email to firstname.lastname@example.org
from your gmail account, do see anything related to this process in your mail log?
Oh, I've just run
dig MX grupodatel.com
and that's the result:
; <<>> DiG 9.2.4 <<>> MX grupodatel.com
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2905
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;grupodatel.com. IN MX
;; ANSWER SECTION:
grupodatel.com. 7200 IN MX 0 mail.zoneedit.com.
grupodatel.com. 7200 IN MX 0 mail5.zoneedit.com.
;; Query time: 198 msec
;; SERVER: 18.104.22.168#53(22.214.171.124)
;; WHEN: Tue Nov 8 16:32:07 2005
;; MSG SIZE rcvd: 84
That means that your email arrives at mail.zoneedit.com or mail5.zoneedit.com. I don't think your server is one of these so you have to change the MX record for grupodatel.com first.