Undeliverable email - OK with webmail but not OE why?

[Gavona]

I send using Outlook Express to an email address from my addressbook, used previously with no problems. The email is not received and I get a message like this:

The following message to <xxxx@xxxxxweb.com> was undeliverable.
The reason for the problem:
5.1.0 - Unknown address error 517-'SPF fail mk-filter-2-a-4.mail.uk.tiscali.com: Address does not pass the Sender Policy Framework'

I send the same email using the same ISP but the webmail facility and it works. I can receive from the address but replies fail in the same way.

I use XP, AVG, AVG antispam, Windows firewall, BlueCoat K9 web protection.

How to sort this out?

Gavin

 

[smah]

Talk to your ISP. Their SPF record is not set correctly.