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Changed ISP and all internal PCs now fail to send email.

Ok, this is weird one!

I changed providers this week, and of course the static IPs changed for my router and W2k3 server, all internal PCs are under DHCP and working fine regarding Internet.

But, MS Outlook 2003 in all of the clients stopped working to send emails (yes only to send) I already have the clients authenticating with the SMTP server and what happens is that whatever email sent get stuck in the outbox UNLESS it is NOT HTML!

I have tried many different tests but I am right now running out of options! I also run the SCANPST tool without success. BTW even a test with an email account on the new ISP failed to send!

Thanks for ANY tip!


Task 'USER - Sending' reported error (0x800CCC0F) : 'The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP).'

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Outgoing SMTP address

In reply to: Changed ISP and all internal PCs now fail to send email.

Have you change the Outgoing SMTP address to the one provided by your new ISP in MS Outlook? If so, check and see if the authentication setting is correct. Most ISP now requried authentication for using their SMTP server. You should be able to find those information from you new ISP web site support section. If you are using your own domain name ( as your Outgoing SMTP server, check and make sure you are using your new ISP DNS servers. Thats all I can think of right now.


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I found what was the problem!

In reply to: Outgoing SMTP address

After running all possible troubleshooting routines I decided to go to the basics! I disconected everything and began reconecting and testing step by step, well it turn out to be the wifi router I have there! Somehow it is blocking pachages on port 25 and this coincidentally began after the ISP switch. I simply set it to be only an Access Point and set my server to route and voila... all up again! Well now I got to deal with the routers' manufactory to discover what is the problem.
Thank you anyway!

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