SMTP Problem

If i try to send an attachment with an email over approx 100kb i get an SMTP error. The problem exists with either Thunderbird or Outlook 2007.
Thank you

problem might be with your ISP smtp server. did this work previously but not now? what does the error code say?

Can you send any mail or is it just a problem with attachments? Does it happen with the same recipient or others as well?

Thank you for your quick response people, i can send an email without an attachment to anyone. I can send an email with an attachment less than 100 kb to anyone....any sort of file. I cannot send any attachment greater than 100kb of any file type. It is not my ISP, if i revert to my Vista image all is well. My laptop (Vista) is working well also. There is no error code, just the...check your smtp server.

Go to your account settings. Select more settings then advanced settings. Increase the server timeout value. My default is 1 minute. Then try again.

Also, have you applied the service packs to office? If not, you should.

Increasing the time out has not helped, problem still occurs. An office update will not solve the problem, i prefer to use Thunderbird.
I'm heading back to Vista shortly i think.

I have a clean install of a win 7 pro x64 on a 1yr old vista Dell H2C. I installed office 2007 enterprise and everything works fine, except emails with attachments over 100kb like this guy is saying. I have tried everything. Also just to clarify it's an exchange email account hosted with Sherweb. I can send emails all day but when I try to email something with a attachment over a certin size bam it just sits in my outbox for ever then sometimes it disappears but never send to the intended recipenent. Also if I start to send a attachment and a regular mail with no attachment the regular mail goes out even while the attachment mail is trying to send.

I am stumped...any sugestions would be appreciated....
Also have tried server timeout and nothing.

Since i've had no luck resolving this problem i've reverted back to Vista. Perhaps SP1 when it come out might fix my problem.

I've had the same problem!! In Vista everything worked fine. Knowing that Win7 doesn't have native mail, I installed Thunderbird. Mail comes in just fine....but can't send anything. Just get an alert that SMTP is not working. So figuring it might be Thunderbird, I reinstalled Outlook 2003.....same problem - no SMTP success.

What's going on here? Is this a deliberate attempt by MS to force users to webmail???