Emails Stuck in Outbox - Error 521 Connection Rejected

[Padraig Mac Grianna]

Hi all,

I am having a problem with outgoing emails using the Outlook email client. I have been in touch with the company hosting our email and we have checked the client settings inside out at this stage. All the settings are correct. Here is the situation.

At school (IP address range 87.38.48.x) I am unable to send emails. They just sit in the outbox and when I 'Send and Receive' it gives me the following error.

Sending' reported error (0x800CCC61) : 'Your outgoing (SMTP) e-mail server has reported an internal error. If you continue to receive this message, contact your server administrator or Internet service provider (ISP).  The server responded: 521 connection rejected'

I can receive messages without a problem.I have changed port settings (using 110 and 25), checked outgoing authentication is on, made sure SSL is disabled, etc but to no avail.

The strange thing is that when I use the same settings at home it works without a problem (IP address 192.168.8.X)

One other computer (Desktop) in the school has the same problem. (different email account using the same domain). This machine is running Windows XP, so I thought it may be related to this. I used the exact same settings on another machine to check if it was something related to that particular email address but it works fine on another desktop (running Windows 8).

My laptop is running Window 7 Pro. I tried turning off the anti-virus temporarily to see if that was affecting it but no luck.

Does anyone have any idea what may be causing this? 

Go raibh maith agaibh,

Pádraig.

[Mary Linehan, IT Co-Ordinator]

I had a problem when we first introduced Google Apps - only with some versions of Microsoft …. I played around with the ports  - used different ones to the ones recommended and eventually found an answer.

Kind Regards

Mary Linehan, 

IT Co-Ordinator

mary.l...@midletoncollege.ie

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[Seaghan Moriarty]

A Phádraig a chara,

 

Not being able to SEND is related to your OUTGOING (SMTP) settings.

At school, your SMPT seems to be refusing to deliver/allow the outgoing mail

At home, your SMPT is allowing the outgoing mail through.

 

Eg  If you have SMTP set to mail1.eircom.net, then at school (which uses UPC as an ISP for example) outgoing email does not work. However, at home (where you use Eircom as your ISP), then all your outgoing email will work.

 

Think of it like this: if your email SMTP setting is set to Blue, then while you are on Blue ISP, your email will send.

 

Exceptions: there are loads (SMTP authentication, pop-before-smtp, open relays etc) – however the above is a good general principal.

 

Possible fix: one good approach would be to find a machine that is sending outgoing mail OK – and then copy those SMTP settings to the problematic machine.

 

HTH

 

Kindest Regards,

Seaghan.

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[Padraig Mac Grianna]

Thanks for the replies/suggestions.

The SMTP settings that I use at school is the same as all the other teachers and it works fine for them.

Outgoing Mail Server (SMTP): mail.blacknight.com

Ports Settings are: Outgoing Server (SMTP) = 25 (I also tried 587)

We have around 16 laptops in school all with the same setup (I set them up) and we are only having a problem with my laptop and the secretary's desktop. The only thing that I can see being different was that we had two email accounts setup on these email clients. I have since removed the second one. I have even deleted the original one and set it up again but I still have the problem.

When I am at home I have not changed the settings and I am using O2 Broadband and it works. Could the NCTE router be blocking my outgoing email?

Pádraig.

[i...@colaistemhuireask.ie]

Will changing your ip test if the router is blocking your traffic?

Could your account be blacklisted for spam?  Don't know how the blacklisting works, just throwing out ideas.

Regards,

Michael

[Padraig Mac Grianna]

Yes as it turns out my ip address was blacklisted by fortiguard for some reason.
I just had to request it to be unblocked and four days of head scratching was over!☺

Padraig.

[Seaghan Moriarty]

Sorry Padraig,

 

Looks like there are too many unknown factors to hazard a guess – getting someone on-site would be the best way forward.

 

Also on blacknight, question 3) on this page: https://help.blacknight.com/entries/22941878-I-cannot-send-email  might help confirm your settings – and last thing, enter your (viewable by the wold) IP here (http://mxtoolbox.com/blacklists.aspx) to see if you are on a blacklist. It does look like the server is actively blocking your mails (might be blacklist, might  be a limit that BK have on number of emails from certain IP etc.)

 

(PS any 192.168.etc. is NOT your (viewable by the wold) IP address)

 

Sorry!

 

Kindest Regards,

Seaghan.

[G P Ashe]

One of the drawbacks if you are using NAT and single public IP is that if you end up on a blacklist everyone will be affected and it can take time and effort to get de-blacklisted. 

It is one reason to avail of NCTE/PDST/HeaNet seemingly unlimited pool of public IPs!

-- gpa

[Hassan Dabbagh]

Good service provided by NCTE/PDST/HeaNet but I wouldn't say Endless :) I'd imagine they're doing a fair bit of IP juggling.


Hassan Dabbagh
087 9044716

> On 12 Sep 2014, at 18:34, G P Ashe <gpa...@gmail.com> wrote:
>
> NCTE/PDST/HeaNet