Problems with avast! and SMTP sends via Outlook -- started just this week!

Starting sometime early this week I began being unable to send email from Outlook. I don’t believe the two are related, but I had installed Firefox around the same time and have since uninstalled it. We did quite a bit of testing to confirm my configurations were proper but all was good. As a last attempt I disabled the Internet Mail provider and I can now send emails from Outlook without problems.

My logs indicate that only virus file updates had occured since the new program release in April.

You don’t say what version of Outlook (not express ?) you are using.

If MS Outlook ensure that the avast plug-in isn’t disabled.
Outlook 2007 > Tools > Trust center > Add-inns > Manage Disabled items.
Outlook 2003 > Help > About > Disabled items
Outlook 2000 > Tools menu > Options > Other > Advanced Options > Add-In Manager.