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[address@concealed]

hello,
I'm looking for help for the following problem :
I've two servers
-a sympa/wwsympa/mysql server (I'm using sympa/wwsympa v 3.1b10)
-a mail server (smtp-pop)
I've the following problem :
a list is made via an sqlquery:
the result of my query is  for exemple 1816 records (adresses) that i can see 
in wwsympa (review)
all the subscribers have a local adress from my domain.
when i send a message to this list only a part of the 1816 adresses receive 
my message (1149 in my case I check it in /var/log/maillog of my mail serever)

in my sympa.conf
i ve set as recommended  
maxsmtp 100
i 've leave
nrcpt  to  25

when i check in sympa.log, i see :
message for ...accepted ...(35 seconds 73 sessions)
that seems correct 73*25=~1816 , so i think that all the messages are sent 
from my sympa server
Must I change something on my smtp server, oon my sympa server ?
Is it an excessive load for my machines?
Why don't i get errors messages on both servers  ?

ps -With lists with a lower number (~800) of subscribers ( extracted from an 
sql query too) there is no problem.

Thanks in advance