Basically, never seen it use before (AFAIR) and wanted to know what
others thought, seen or knew something about it. It turned out
something like a "greylisting like" behavior. A subsequent 4th retry
(15 mins, 15 mins, 30 mins) did successfully send it.
The only thing that crossed my mind (after seeing this) was whether
using 40z was correct for a retry (without change) and the x0z
contradicting it (i.e. syntax error). It seems 40z should never apply.
John C Klensin wrote:
Hector, could you clarify what you wanted to find out from this