If you have not send emails in Ireland on your broadband you may have to change SMTP settings, see below to see how to change your settings.
N.b: The better way:
If your hosting company hosting your email they might support Authenticated SMTP sending.
Use this since it will allow you to send emails who ever your connected to.
Also try to connect using SSL encrypted under SMTP settings, if this fails try setting your outgoing mail seetings to one of the following below relavent to what broadband your using.

Irish Broadband SMTP Server
Irish Broadband SMTP (Outgoing) Server:

smtp.irishbroadband.ie.
eircom-logo
Eircom SMTP (Outgoing) Server:
mail1.eircom.net OR mail2.eircom.net
Magnet Broadband SMTP Server
Magnet SMTP (Outgoing) Server:

smtp.magnet.ie
upc Broadband SMTP Server
Virgin Media/NTL/UPC SMTP (Outgoing) Server:

smtp.upcmail.ie
Ice Broadband SMTP (Outgoing) Server:
mail.icecomms.net
vodafone.ie
Vodafone SMTP (Outgoing) Server:
NONE – You will need to use a gmail account or something like sendgrid.
o2 Broadband SMTP Server
O2 SMTP (Outgoing) Server:

smtp.o2.ie
Clearwire SMTP (Outgoing) Server:
smtp.clearwire.ie / mail.clearwire.ie
Digiweb SMTP (Outgoing) Server:
smtp.digiweb.ie
Imagine Broadband SMTP (Outgoing) Server:
smtp.imagine.ie
Perlico SMTP (Outgoing) Server:
mail.perlico.ie
3 SMTP (Outgoing) Server: Mobile broadband with 3 mobile Ireland
mail-relay.3ireland.ie
Gmail SMTP Server
smtp.gmail.com (use authentication)
Use Authentication: Yes
Port for TLS/STARTTLS: 587
Port for SSL: 465
    Meteor:
meterologo
Use your email account smtp. Meteor do not block outgoing mail settings.
If your still having problems in your office or business please contact us or our IT Support team can help you.