outlook 2000 emails not being received

[SherryJ]

I've been using Outlook 2000 on the same computer (W2K), same Outlook program for several years. I send many emails each day to different users in the same domain - ie: johndoe@anycompany.com or janedoe@anycompany.com. In the last 3 weeks the recipients at "anycompany.com" have not been receiving my emails. They show up as sent in Outlook and I'm not getting any "mail not deliverable" messages. I spoke with their ISP people and nothing has changed on their end.
I created my email account on a computer running XP SP2, Outlook 2003, sent an email to "anycompany.com" and it was received. Deleted my account on my W2k machine, recreated it, sent another email to same person - they received it, so I thought the problem was solved, however I now find out that it's not. My emails once again are not getting through.
All my other emails are being received and I can receive email from "anycompany.com".
I have run "detect & repair" on Outlook, but didn't make any difference. I use NAV, Polesoft anti-spam, Microsoft Antispyware, AdAware Antispyware, and A-squared Antispyware.
Please help!

[Snurfen]

It's extremely unlikely that your end is stopping the mail. Stick a read reciept and tracking reciept on a test. Make sure you put some text in te body and send it off. See what happens.

Someone somewhere has messed up, unlikely (though not unheard of) to be a prob with the ISP. More than likely to be an issue at the recievers end. Check that they haven't lost any other emails lately (the company, not just the recipient). If they are using Exchange, it's likely they have had an outage where the log file became unavailable, or more likely corrupted OR the final destination address has or had a problem with the mailbox file.

Welcome to CTH by the way

[SherryJ]

Thanks, Snurfen. I know how to ask for a receipt when the email has been read, but how do I track it?

(Thanks for the welcome, too!)