At 12:38 30-08-2006, Hector Santos wrote:
We have implemented a GreyListing system. The "specs" indicate to use a 451
This isn't an error in processing. It is policy related and would a
450 is better suited.
Based on your report, they are blocking you for 300 seconds or 5 minutes.
That is definitely too long in my opinion and in the opinion of others in
the greylist support list.
Retrying within one minute is too short. Note that the reply code is
not specific to greylisting.