problem sending emails - Client host rejected: Access denied

[Adams_16v]

ok iv recently setup my new online shop, and as part of it have setup numerous email addresses.

All working fine up untill a few days ago.

Now my business partners email addresses wont work. Receiving is fine, but when sending via smtp via Outlook 2003 an instant 'system administrator' message is received stating:

554 <unknown>[xx.xx.xx.xx]>: Client host rejected: Access denied (x's being an IP, i cant remember it exactly off hand)

Strangely enough he had just bought a new laptop when it suddenly stopped working. (not sure this is just a co-incidence though)

I have tried adding the email settings to my home pc which is using a different ISP and I get the following message when trying to send out:

554 <85-211-224-211.dyn.gotadsl.co.uk[85.211.224.211]>: Client host rejected: Access denied

My ISP is Nildram which is gotadsl.co.uk

Iv contacted the hosting company who host the site and email addresses etc, and they cannot replicate the problem.

I can send fine from my computer from 3 other email addresses using the same domain name *@i-modish.co.uk

Works fine from webmail.

Iv changed the password and all ok.

Checked firewall settings etc, but cant see it being that as my email addy works fine.

Any ideas?

Wondering if he's on some kind of blacklist that some ISP's use to block certain email addresses from sending emails?

Cheers for any help

 

[Adams_16v]

sorted it lol.

seems fukin weird tho that i need to enable outgoing authentication on this address only but not on any others.....BEARDY WEIRDY!

 

[Daz]

It's to stop open relaying.