For several years now we've been sending a weekly price list to customers (about 150 in total) via our SME server. Recently we've had complaints from some customers that they're arriving much too late (up to 2 days after sending). I've tracked it down to customers from one ISP (44 of the 150 addresses are with one ISP) - here is the text from the qmail logfile:
2014-06-17 15:32:07.509441500 delivery 5090: deferral: Connected_to_XXX.XXX.XXX.XXX_but_greeting_failed./Remote_host_said:_421_mwinf5c63_ME_Trop_de_connexions,_veuillez_verifier_votre_configuration._Too_many_connections,_slow_down._OFR004_104_[104]/
I guess that it's maybe some kind of anti-spam thing - too many mails from our server at once - it used to work fine and, apart from applying updates, we haven't changed anything. It's maybe not a SME problem but I'm hoping that there's some setting I could change that would "slow down" our sending.
Server is SME 8 standard, no contribs, all updates applied.