Vista Email Issue and Fix

Vista SMTP Connection Issue - Error 0×8004210b

Have you had problems connecting to an SMTP server ?

Recently we have had email issues with Vista and Outlook with sending emails. Although we could receive emails via Outlook, they wouldn’t send. Most commonly, but not always, with the error 0×8004210b.

If you search for this error, you cannot find the solution anywhere, hence the reason for this post. The most common suggestions that we found are to turn off McAfee or Norton antivirus, delete and re-add the email account, re-install outlook or the most drastic of them all, re-install Vista. We tried all except the re-installation of Vista, and nothing worked (although we didn’t let Norton anywhere near our machines in the first place!)

Error 0×8004210b Vista SMTP issue Fix

After about 6 hours of searching, we finally found something buried away on the Microsoft technet forums.  After fine-tuning it we could eventually send emails and this has also solved the error on our clients PCs.

Below, we have listed the fix that we used to solve the Outlook 0×8004210b SMTP issue:

1. Click the start menu and in the search box at the bottom, type cmd. This should bring up a list above the search box, with cmd.exe at the top.

2. Right-click on cmd.exe and click run as administrator. Depending on how your windows was set up, you may get a question box asking if you wish to continue or not. Press continue and you will get window with a black background, some white text and a flashing cursor.

3. Copy the line below into this window and press enter. Please be sure to copy it exactly, or if you wish, highlight the sentence below, right click and hit copy, then next to the flashing cursor, right click and press paste, then enter. You should get a message simply say “OK”.

netsh interface tcp set global autotuninglevel=disabled

4. Do the same as number 3, only use this code below:

netsh interface tcp set global rss=disabled

5. That is it done. You can now close the window an send those emails stacked in your outbox.

Although we have tried this 0×8004210b fix on 12 machines and it worked on all of them, both in the office and on clients machines throughout the UK, we don’t claim that this is the be all and end all of fixes, as your machine may have other issues that is preventing you from sending emails, but this worked in our case. If it works for you, please drop us a quick email to let us know.

12 Responses to “Vista Email Issue and Fix”

Donna Says:

I am still receiving the same error message. Do I need to somehow reset what I have done? I was going to repeat the process but when you search cdm there are no files found. Any new suggestions?

The Big Man Says:

Hello Donna,
I don’t mean to state the obvious, but it could be that are you searching for cdm, as you state above, as it should be cmd.
I can’t see that there is any other reason for no files being found.
Get back to me if I’m misunderstanding what you are asking.

Jon Conant Says:

I tried this on XP and it doesn’t work. NETSH INTERFACE doesn’t have TCP as option.

That may be Donna’s issue.

The Big Man Says:

Jon, this is a Vista fix, not an XP fix. The clue is in the Title of the blog article, “Vista email issue and fix”. :)

Seriously though, it’s good to know that if someone else is having the same issue in XP, they shouldn’t bother trying this Vista fix. Thanks for the input.

Mohammed Says:

Thanks for the fix. Its works for me

Gez Thompson Says:

I had 7 emails that went to my out box that I had already sent so I quickly dragged them to my sent box from then on I could recieve emails but every time I sent any it tried to send the 7 emails that werent there. I tried your solution and itworked first time - once I had closed outlook while I performed your solution. Thanks, I have been trying for 4 hours to sort this, until I searched and came across your solution on the web. Cheers again.

Jack Summerfield Says:

It didn’t work for me. This error just occurred out of nowhere. I’m running Windows Mail via Google Mail on Vista Home Premium. Can receive but not send.

Do you have any thoughts on this?
Thank you.
Jack in Oregon, usa

The Big Man Says:

Hello Jack, We’ve never tried the fix in the configeration you are using; windows mail via Google mail. We have only tested it on Outlook and Outlook Express. This works on the basis that it uses smtp and googlemail may use imap instead. sorry I can’t be of more help, but we can’t test it without setting upwindows mail via googlemail and we don’t have the time. Why are you not just using Outlook anyway? It would sort your problem. Have a fine day, Kennie

Miguel Santos Says:

Didn’t work for me… I’m using outlook for a google account and for a business account, but the problem with the 2nd hasn’t been solved yet…

What could I have done wrong? Thanks for the help.

Sorry Miguel, I can’t guuess at what you are doing wrong. We have used this fix on several friends’ machines and it has worked first time every time, following the instructions above. I can only suggest that you try again. BM

Laurie Says:

I know that it has been a long time since anyone has posted to this but out of the blue I started having issues with Outlook and despite having all updates current on my machine I couldn’t find a thing that I had done different.

I have searched all day when I came across this post and just wanted to say thank you… It worked great!

Scott Says:

It worked…thanks.Any clue on what the “fix” fixes? In any event thanks again.

Cheryl Says:

I am really struggling with this issue but on XP, i know this is for vista, but its the nearest anyone has come to accepting the problem! any thoughts from those with XP who had it previously? I think you’ll continue to struggle, I’m afraid Cheryl. XP came out 11 years ago and was superceded five years ago and any support for it is due to be dropped in a year or so. Maybe think of upgrading your system :)

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