Outlook send issues - messages are not received

By norman ·
We are having problems sending from Outlook 2000 and 2003. The messages are not received. There is no error message nor do the emails bounce back. Messages are received with the same settings with Outlook Express and Thunderbird. The issue is on several different machines using different ISPs. I tried deleting and recreating the profiles, starting Outlook in safe mode, and followed Microsoft?s instructions for password issues even though we weren?t having them. I deleted the profiles in the Registry, it work for two days. That isn?t working as a solution either. My hosting company cannot reproduce the problem testing Outlook using my account. Their test messages are received.

Thus, the problem doesn?t seem to be the ISP, the settings, the host, firewalls, or antivirus software, but with Outlook on our machines.

Does anyone have any ideas?

Thanks Everyone.

Additional Information - When I say I cannot send email, it is to outside addresses. We can send to internal addresses. The host company says that is because the message doesn't hit their outside mail server. If I put a false email address such as test@gmail with out the .com, I get a 550 error message.


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All Answers

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What port(s) are you sending your emails through?.

Find what kind of ports you are using and see if they are correct. If not then rectify the ports by giving them/it the right port number(s) such as "port 80" or "port 110".

Please post back if you have any more problems or questions.
If this information is useful, please mark as helpful. Thanks.

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Ports 25/110 and 587/110

by norman In reply to What port(s) are you send ...

I have tried the ports both as 25 / 110 and 587 / 110. Niether works in Outlook both both work in Outlook Express and Thunderbird.

Its so puzzling that everything works fine accept in Outlook.

Thanks for the reply.

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Completely uninstall antivirus suite

by Monice In reply to Outlook send issues - mes ...

You say it isn't the Antivirus. I have had this issue many times and it was the Antivirus or Spam Filtering. Typically any of the Internet Security Suites. When you tested did you just disable these? I had the problem persist when just disabling these services. Have you tried it by completely uninstalling Antivirus and Spamfilters? That has resolved it for me many times.

Good luck.

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Antivirus Questions

by norman In reply to Completely uninstall anti ...

Thank you for the reply.

Good point that disabling doesn't work. I have Norton Disabled. I don't use a Spam filter.

Question - Can I test this by starting up in Safe Mode with Internet? Norton wouldn't load would it?

Question 2 - If it was Norton blocking Outlook, would it also block Outlook Express and Thunderbird, because they work?

Additional information - I can send to myself and other internal addresses. I can't send to external addresses. The hosting company said that is because internal mail doesn't go through the mail server. Also, if I send to a false address - like test@gmail with no .com, I get a 550 error message. So I feel it hits the mail server. The problem is the hosting tech guys can send on Outlook?

Its so crazy.

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by Monice In reply to Antivirus Questions

I have previously had the same exact symptoms in the same situation. I have tried everything not to have to uninstall my customers AV and could not remedy the situation without uninstalling. I have seen these issues mostly with Norton and McAfee security suites. You could try safe mode with networking. Let me know if that works.

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550 error message....

You receive a SMTP relay blocks error message when you send e-mail messages in Outlook

When you send messages, you may receive an error message that your message cannot be sent because of Simple Mail Transfer Protocol (SMTP) relay blocking. The exact error message may vary, depending on your Internet service provider (ISP). However, it is similar to the following error message:
The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was '<>'. Subject: '<Test>', Account: '<Test>', Server: '<>', Protocol: SMTP, Server Response: '550 <>... Relaying Denied', Port: 25, Secure (SSL): No, Server Error: 550, Error Number: 0x800CCC79

This behavior may occur if you have one of the following configurations:
? You are logged on to a Local Area Network (LAN) that has an Internet gateway and you try to send messages through an ISP's SMTP gateway.
? You are logged on to an ISP and you try to send messages through another ISP's SMTP gateway.
? You are using a cable modem or ADSL to get to another ISP and you try to send messages.

This behavior affects all messaging clients, regardless of the manufacturer.

To resolve this behavior, contact your ISP for help. The e-mail client does not cause this behavior. From a messaging client standpoint, there are no solutions for customers whose ISPs block all SMTP Relay traffic.

Most of the new SMTP e-mail gateway software permits relaying for specific IP addresses. This is how cable modem and ADSL users can continue to use their same ISP. The cable modem or ADSL provider must provide the customer a static IP address, in turn, the customer's e-mail ISP allows relaying for that specific IP address. Banks of IP addresses can also be permitted, which may provide a work around for some corporate customers who access ISPs through their corporate LAN.

If the error message that is described in the "Symptoms" section of this article is random, it is possible that your SMTP server is checking whether the domain or the recipient name actually exists before sending the message. If the recipient's e-mail server is temporarily down or unavailable for another reason, such as high network volume, your SMTP server cannot verify the address and may reject the relay. In this case, action is not required. The message is sent when the receiving server is available again.

This behavior may become more common as ISPs start to take action against SPAM messages. SPAM is flooding the Internet with many copies of the same message in an attempt to send the message to people who would not otherwise choose to receive it. Most SPAM messages use an automated system to send commercial advertising, or mass marketing messages. SPAM costs the sender very little to send; most of the costs are paid for by the recipient or the e-mail providers.

Some ISP's are fighting SPAM by requiring each user to be dialed directly into their system to send messages through their SMTP gateway. This is an easy way to control SPAM, but may affect some users who tunnel into their e-mail account from another ISP.

MSN, the Microsoft Network, is one example of an ISP that has imposed SPAM blocking. Additionally, MSN has imposed restrictions whereby if the e-mail address in your Internet Account properties does not match that of your MSN account, you may also receive SMTP blocking errors. This affects users who receive messages with two different Internet addresses, but that want the same reply address on both e-mail accounts. Other ISP's implement similar strategies.

To send or receive messages through a LAN, additional ISP or DSL and similar connection devices through MSN, the SMTP server settings must be set to secure.

MSN e-mail server settings for a LAN, DSL or third-party connection must be set to

Examples of SMTP Relay Blocking
? Employees have personal ISP accounts at where is your Service Provider's domain name. They use the company's corporate LAN to access their messages, and they have any problems sending or receiving. One day they start receiving SMTP blocking errors when they try to reply to messages that they have received from They contact technical support and are told that just installed new SMTP gateway software which prevents SMTP relaying. Now the employees can receive messages through the LAN, but cannot send messages because they're not connected directly to
? A user has two ISP accounts, one with and one with, where and are the Service Providers' domain names. The user dials into and can send and receive messages from both accounts without problems. One day the user connects to and tries to send messages through and receives blocking errors. The user connects directly to and can still send and receive messages with both accounts. In this example, implemented SMTP relay blocking and did not.

Please post back if you have any more problems or questions.
If this information is useful, please mark as helpful. Thanks.

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Outlook send issues and error messages

by norman In reply to 550 error message....

Wow. Thanks for the great post. Now I understand 550 errors.

However, I am only getting a 550 error when I purposely put an incorrect address to see if my send is hitting the mail server. I had assumed the error came from the mail server versus the ISP.

The problem is that when I sent an email to an address outside of my domain from Outlook, it never arrives. There is no error message nor does the email bounce back.

Yet, Outlook Express and Thunderbird work?

My hosting company can sent emails from my accounts from Outlook, so they say it isn?t them but us.

I had ruled out the ISP as on site we use XO, but off site its Comcast, Verizon, and Charter, and we all have the problem. But maybe we need to look at the ISP?

The other suggestions I have had are the AV. I?m going to try starting on Safe Mode w/Networking. I just wonder that if the AV was blocking Outlook, wouldn?t it block Outlook Express and Thundbird also?

As the problem is both on and off site, I also ruled out the Router/Firewall on site.

I have deleted and recreate the accounts, etc., etc.

So I hope it?s the AV as otherwise I don?t know what it could be?

Thanks again.

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Question.Doesn't Comcast need a staic IP address?.

And if so, maybe this could be the cause. Outlook is picky to say the least when it comes to sending emails. So i would look at your sending and receiving port numbers and see if there is a conflict with these. Test out what port numbers work and what do not, i do not think that it will be your AV. Firewall maybe, maybe in the router firewall. Just a thought.

Please post back if you have any more problems or questions.
If this information is useful, please mark as helpful. Thanks.

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1/2 Solved - mixed results in Safe Mode

by norman In reply to Question.Doesn't Comcast ...

The issue is so nutty.

I restarted in Safe Mode w/Networking under Administrator to test without AV. Having never used Outlook is the Administer, I entered in a new account, was asked for the password at send, and it worked!

Thinking I had the solution, I restarted in Safe Mode w/Networking again and logon as Myself, and it didn?t work.

I don?t know what that means?

What would load under my username and not the Administrater acount?

I also just don't understand why when an email is sent to both internal and external accounts, the internal arrives and the external does not. Doesn't that mean the message made it through?

If the message was blocked, the internal wouldn't make it. Correct?

Thanks everyone.

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PST Folder Question

by norman In reply to 1/2 Solved - mixed result ...

Thought - The difference between the Admin and my user accounts is they would have different PST files.

If I run ScanPST.exe, would that screw up all my folders and dump everything into one recovery folder?

The other thing here is that would mean we all have a problem with our PST files and as the problem comes and goes for all of us together, that would mean we all have the PST issues come and go at the same time.

ADDED - That wouldn't make sense that we would all have PST file problems come and go at the same time. Thus, it can't be that.

Since August 28th, we have had the problem for come and go several times.

I have deleted the Protected Storage System Provider in the Registry, deleted and recreated the accounts over and over again. Nothing seems to solve the problem or I should say slove it for good.

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