Can receive but cannot send

We are using Mdaemon 9.6.6 and users with Outlook 2003 and 2007. Internally we send and receive mail with no problems. Our mail system is setup same for pop and smtp. When we are on the road we can hit send/recieve and collect mail but when we reply or send a new message it wil either go out into lala land or there is an error. We have Sprint PCS cards and when using those on the road the connections are flawless with sending and receiving. I am not certain why the aircards work and not a HS connection.
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Have you

(1) specified your Mdaemon server to be the SMTP server in Outlook settings (  

(2) opened up Port 25 outgoing on the laptops - if the ISP you are using doesn't allow outgoing connections on Port 25, you can set Mdaemon to listen on a different Port as well as 25 (e.g. Port 587) - don't forget to Port Forward that port though.  

(3) Are you authenticating in to your Mdaemon server from your laptops (to ensure there is no possibility of an Open relay)?

Please respond even if it's none of these issues
Sjef BosmanGroupware ConsultantCommented:
Do you have ANY logs of your system?

If you test, test bottom up:
1) cabling
2) network presence
3) TCP/IP presence (ping)
4) DNS ok
5) telnet 25
wyliecoyoteukIT directorCommented:
You are probably set up to allow relay from local addresses only. you need to allow authenticated relays.

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I think moorhouselon& is on the right track.  A lot of ISP's have stopped allowing connections to port 25 unless it is one of their SMTP servers.  This is to stop their networks from being used to send SPAM.  So you may need to change your SMTP server to listen to a port other than 25.
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