550 Bounce

[Cloud9]

Hi

My server (with csf and mailscanner installed) is bouncing mail sent to me from a yahoo account

They are getting the following bounce error

Remote host said: 550 signature_incorrect [BODY]

Where do i look to see why this is being bounced ? (It never happened before mailscanner was installed)

[thurmma]

Hello,

I am having the same issues. Any word on why this is happening yet or how we can fix it?