Greetings,
You did what I would do, decreased the reconnect to the number it often failed at. Since this didn't help, it's also possible that your server has a strict limit on script execution time.
The following code, when pasted into a .php file, uploaded, and browsed to, should indicate whether or not your server has a time limit:
<?phpini_set('max_execution_time',0); function timeWait($microtime) { $timeLimit = $microtime + array_sum(explode(" ",microtime())); while(array_sum(explode(" ",microtime())) < $timeLimit) {/*nothing*/} return(true); } echo "Testing 1s...<br>Process started at " . date("H:i:s") . " and " . current(explode(" ",microtime())) . " nanoseconds.<br>";flush(); timeWait(1); echo "Process completed at " . date("H:i:s") . " and " . current(explode(" ",microtime())) . " nanoseconds.<br><br>"; echo "Testing 5s...<br>Process started at " . date("H:i:s") . " and " . current(explode(" ",microtime())) . " nanoseconds.<br>";flush(); timeWait(5); echo "Process completed at " . date("H:i:s") . " and " . current(explode(" ",microtime())) . " nanoseconds.<br><br>"; echo "Testing 35s...<br>Process started at " . date("H:i:s") . " and " . current(explode(" ",microtime())) . " nanoseconds.<br>";flush(); timeWait(35); echo "Process completed at " . date("H:i:s") . " and " . current(explode(" ",microtime())) . " nanoseconds.";?>
If all goes well and your server does
not have a strict time limit, you will see 3 copies of "Testing ..." and "Process completed".
It did sound like your host was talking about inbound email, but I'm not sure. ListMail personalizes each message and doesn't set more than one recipient per message, but some spammers might...
I would ask your host if there are any daily or hourly limits on outgoing email and whether or not there is a strict time limit on PHP scripts. On many hosts they can allow scripts to run as long as necessary by disabling PHP "safe mode" for your domain.
Regards, DW