I am a freshman,and I first use the exim4.89 on ubuntu 16.04,I found this problem ,the log show that:
3900 SMTP>> 421 Too many concurrent SMTP connections; please try again later.
3900 LOG: connection_reject MAIN
3900 Connection from [**********] refused: too many connections
3900 Listening...
,so where can I set the max connection number ,I didn't see any useful options in /usr/exim/configure file,thank you very much