Slackware-13.1: Upgrade postfix-2.8.7 to -2.9.0; Sending error: 421
Yesterday, postfix-2.8.7 worked fine both receiving and sending mail. I upgraded to 2.9.0 using the SBo script that I've used to build and upgrade postfix for a number of years. Stopped postfix, ran upgradepkg, restarted postfix.Since then I can receive messages but cannot send them. I use alpine-2.0.0.
When I try to send a message this error appears:
Sending error: 421 SMTP connection broken <reply>
An hour's worth of searching with Google found only that this error message means "ownership or permissions of sendmail binary are wrong." Here, /usr/sbin/sendmail is owned by root.root with perms 755. All postfix components (smtp, smtpd, qmgr, trivial-rewrite, etc.) are owned by root.root with 755 perms.
Naturally, e-mail communications is critical to my business and I'm totally stumped on how to fix this problem. Pointers to a quick solution greatly appreciated.