Same problem here. We are unable to send mail using our mail server.
We've tried deleting the mail account completely and re-installing. No effect.
We've tried changing the settings to use SSL/No-SSL, port 25, 465, and 587 no effect.
We've tried setting to automatically mange changes, and not automatically save changes.... no effect.
This is effecting users on 10.10.4 who have taken the latest update.
We have a 10.10 in the lab that was not updated that is working fine, taking updates to see if the same thing happens to it.
When we use SSL port 587 (submission) logs fill up with:
Jul 1 10:37:48 postoffice sendmail[7360]: t61HbmbA007360: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MSA
Jul 1 10:37:48 postoffice sendmail[7361]: t61HbmSA007361: [12redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA
Jul 1 10:37:48 postoffice sendmail[7362]: t61HbmkS007362: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to TLSMTA
Jul 1 10:37:48 postoffice sendmail[7363]: t61Hbmd4007363: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MSA
Jul 1 10:37:48 postoffice sendmail[7364]: t61HbmiA007364: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA
Jul 1 10:37:48 postoffice sendmail[7365]: t61HbmuZ007365: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to TLSMTA
Jul 1 10:37:49 postoffice sendmail[7367]: t61Hbnx5007367: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MSA
Jul 1 10:37:49 postoffice sendmail[7369]: t61HbnrR007369: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA
Jul 1 10:37:49 postoffice sendmail[7371]: t61HbnWm007371: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to TLSMTA
Jul 1 10:37:49 postoffice sendmail[7373]: t61HbnMR007373: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MSA
Jul 1 10:37:49 postoffice sendmail[7374]: t61Hbnnb007374: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA
Jul 1 10:37:49 postoffice sendmail[7375]: t61HbnrF007375: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to TLSMTA
Jul 1 10:37:57 postoffice sendmail[7381]: t61HbvOI007381: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MSA
Jul 1 10:37:57 postoffice sendmail[7382]: t61Hbv2V007382: [redacted] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA