Qmail - 451

I have multiple domains on my server running RedHat EL.. But I have 1 client who is getting a:

SMTP Error 451 - 4.7.1 Please try again later..

when they are trying to send out mail. But I'm not seeing any other client having these issues. Any recommendation on what I can look into?

Thanks,
Jim

 

 

 

 

Top