Occasionally, I hear from clients who suddenly cannot send email, even though they can receive it, using Outlook, Outlook Express, Thunderbird, or another client-based email program. Email they attempt to send is stuck in their Outbox. [NOTE: If you get an authentication error, you will need to resolve that with your email provider; otherwise, read on.] Sometimes their ISP — usually a cable company — decides to block port 25, the standard outgoing SMTP email port, in which case changing the SMTP port to 587 usually fixes the problem. More often than not, however, the problem is with the email they are attempting to send. Here’s how to tell.
First of all, as soon as you attempt to send one problem email, i.e., one that gets stuck in the outbox, subsequent emails are stuck in the outbox, waiting for the first one to go out. Create a new folder within your Inbox. Name it Test, or give it another name if you prefer. Drag the oldest email message — the first one to get stuck — from the Outbox into the new folder. Hopefully, the other messages, if any, stuck in the Outbox will go out. If not, drag them one at a time, starting with the oldest one first, into the new folder, until newer ones automatically go out, or the Outbox is empty. Alternatively, you can drag them all at once into the new folder. Now the Outbox is empty. Assuming that the Outbox did not automatically empty itself, create a test email, carefully addressed to yourself. The subject and body can both just say “Hello.” If it does go out, you are ready to troubleshoot the problem email messages; otherwise, your problem is beyond the scope of today’s post.
More often than not, the problem is with invalid email addresses. One by one, click on the email addresses of the recipients, to verify that they are real email addresses. You will need to fix invalid ones. Quite frequently, your invalid “email addresses” are actually business fax numbers. Microsoft Outlook was designed to show fax numbers as email addresses when you select names via the To or CC buttons. In their infinite wisdom, Microsoft equates electronic addresses, which include fax numbers, with email addresses. One workaround to this architectural flaw is to precede fax numbers with text, such as F for fax. This way, fax numbers will not show up as email addresses. Microsoft offers links to third-party vendors, such as Sperry Software http://www.sperrysoftware.com/outlook/Hide-Fax-Numbers.asp to fix the problem. Your last option is to be careful not to select “email addresses” that are actually fax numbers. For some people this option will work successfully, but for many will result in having to seek this article again in the near future.