Odd outlook 2007 behavior, SMTP mavens please respond

I have a customer with outlook 2007

can recieve no problem

can forward no problem

can reply no problem

new emails seem to disappear into thin air

no error messages trip

can send a new email to themself…no problem.

Emails to my hotmail or yahoo account do not go through although if I send an email from my yahoo account it is recieved in seconds and a reply comes back in a few more seconds.

Comcast says its outlook

Microsoft blames comcast

Any ideas?

comcast uses odd ports, double check your smtp settings against thier online faq.

it’s a start.

Already did, I have the tier 2 guys stumped but I think I just solved it on my own.

It works fine without the graphic in her sig.

any idea why an imbedded jpg would disrupt outbound mail like that.

spam filter?

Dunno, comcast kept saying it has to be outlook but they also could not seem to tell me where the mail is going.

It may have been a spam filtering issue although I did specifically ask if there is a spam flagging issue since this customer regularly sends emails to 30-40 people at a time.

Both people I talked to said no.

I guess it comes down to this:

It was ending up on the sent items list. How is that happening without an acknowledgement from comcasts servers. If so they are dumping it making it a comcast issue to properly diagnose.

I was scrambling for any variable to isolate for when I tried deleting the graphic.

If it’s ending up in the sent items box, I’d say that does indeed mean Outlook has received acknowledgement from the SMTP server that the messages transferred successfully.

If you want to prove this, you could install a logging SMTP proxy, which will capture the whole SMTP conversation between Outlook and your mail provider.


How big is the jpg? Maybe it is a size issue. Can you try adding a different jpg to see if it creates the same problem? Outlook 2007 definitely supports jpg’s in a signature, but recommends they be under 100k.(warning: page has audio).