Could not analyze message

[Paul Houselander]

Hi

I have a customer who cant recieve an email from a certain domain, the
message is quarantined with a quarantine report showing "Could not analyze
message".

The email is very basic, plain text with no attachments.

I tried to get around this by using the Scan Messages ruleset

Scan Messages = %rule-dir%/scan.messages.rules

and set the following in scan.messages.rules

FromOrTo:	default	no
From:	domaina.com	no
FromTo:	mycustomer.com	yes

where domaina.com is the domain sending the email being blocked and
mycustomer.com is the domain recieving. However the message is still being
quarantined.

Can anyone advise what can cause the "Could not analyze message"? or why my
ruleset setup is not working?

Kind Regards

Paul