You cannot use a CNAME on the bare domain name (what you are calling the "root domain"). This is a known limitation of ELB (elastic load balancer) on EC2.
The solution, released recently by Amazon, is to use Amazon Route53 to host your DNS. This integrates with ELB to handle bare domains without CNAME. Your MX records can still be pointed at Google with Route53.
HELO Mistake
The email is being sent out from
mail.megatec.co.il. 62.219.123.33
Not
megatec.co.il. 67.228.132.128
Your helo should be
helo mail.megatec.co.il
SPF - Not Available
Your SPF is either not update or setup incorrectly. A dns query to varies server fail to retrieve it. Even the SOA(ns1.bezeqint.net) failed.
If TXT is setup correctly, ns1.bezeqint.net should relfect the changes within a few minutes, regardless of TTL.
Google dns
# dig @8.8.8.8 megatec.co.il txt
; <<>> DiG 9.8.1-P1 <<>> @8.8.8.8 megatec.co.il txt ; (1 server found)
;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY,
status: NOERROR, id: 42780 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0,
AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION: ;megatec.co.il. IN TXT
;; AUTHORITY SECTION: megatec.co.il. 1800 IN SOA ns1.bezeqint.net.
hostmaster.bezeqint.net. 2010111500 10800 900 604800 86400
;; Query time: 307 msec ;; SERVER: 8.8.8.8#53(8.8.8.8) ;; WHEN: Mon
Dec 24 13:18:09 2012 ;; MSG SIZE rcvd: 94
OpenDNS
# dig @4.2.2.2 megatec.co.il txt
; <<>> DiG 9.8.1-P1 <<>> @4.2.2.2 megatec.co.il txt
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21588
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;megatec.co.il. IN TXT
;; AUTHORITY SECTION:
megatec.co.il. 3600 IN SOA ns1.bezeqint.net. hostmaster.bezeqint.net. 2010111500 10800 900 604800 86400
;; Query time: 338 msec
;; SERVER: 4.2.2.2#53(4.2.2.2)
;; WHEN: Mon Dec 24 13:21:37 2012
;; MSG SIZE rcvd: 94
ns1.bezeqint.net
# dig @ns1.bezeqint.net megatec.co.il txt
; <<>> DiG 9.8.1-P1 <<>> @ns1.bezeqint.net megatec.co.il txt
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11214
;; flags: qr aa rd; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; WARNING: recursion requested but not available
;; QUESTION SECTION:
;megatec.co.il. IN TXT
;; AUTHORITY SECTION:
megatec.co.il. 3600 IN SOA ns1.bezeqint.net. hostmaster.bezeqint.net. 2010111500 10800 900 604800 86400
;; Query time: 150 msec
;; SERVER: 192.115.106.10#53(192.115.106.10)
;; WHEN: Mon Dec 24 13:25:25 2012
;; MSG SIZE rcvd: 94
Best Answer
Your nameservers are badly misconfigured. I ran your zone through the test engine at DNSCheck, and got the following result:
Some DNS clients will still find the MX record for you, but it's really not reliable, and Google's mailservers obviously require an actual working nameserver in order to look up your MX.