Look at your existing sendmail.cf file (/etc/mail); make a copy first, then edit it and look for:# maximum number of recipients per SMTP envelope #O MaxRecipientsPerMessage=100Delete the comment symbol (#) from the second line and change to however many emails you want output per message:EG O MaxRecipientsPerMessage=10 and this should "turn on" that feature.
OK, did that, (reduced to 60 messages initially) and no apparent effect on the problem. Off to reduce down to 10. Presumably there is a performance hit somewhere along the curve...
Oddly, mail sent to a fresh dummy mailing list, (only me subscribed) test@xxxxxxxxxx returns within seconds, but from this (real) list takes 1/2hr or so to come back to me, which is longer than I recall happening in the past. Is that likely to reflect repeated attempts to send the mail or perhaps a problem elsewhere. Are there logs somewhere to examine that would be helpful? (Tempted to cut and paste the membership to another list...)
Many thanks for the ongoing help Tim -- Tim http://yingtong.co.uk