Connection Timeout on aws when Telnet on Port 25

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http://stackoverflow.com – Thanks you for your time. I have just set up a Postfix mail server which is running as MTA in one of my aws instances. I can successfully connect to the localhost through 'telnet localhost 25', and I can send emails to both external and internal email accounts when connected on localhost, however whenever I try to connect through 'telnet zwitch.it 25' or 'telnet mail.zwitch.it 25' I get a connection timeout. I have set up all my records, including the MX record and the SPF record with the values "v=spf1 include:amazonses.com include:zwitch.it -all" and "spf2.0/pra include:amazonses.com inclu (HowTos)