fix from http://luiscachog.me/spamassassin-error-on-vestacp-centos

install/rhel/7/exim/exim.conf

@@ -143,7 +143,7 @@ acl_check_data:
          hosts          = !+relay_from_hosts
          condition      = ${if < {$message_size}{100K}}
          condition      = ${if eq{$acl_m1}{yes}{yes}{no}}
-         spam           = nobody:true/defer_ok
+         spam           = spamd:true/defer_ok
          add_header     = X-Spam-Score: $spam_score_int
          add_header     = X-Spam-Bar: $spam_bar
          add_header     = X-Spam-Report: $spam_report

install/vst-install-rhel.sh

@@ -1124,6 +1124,13 @@ if [ "$spamd" = 'yes' ]; then
     chkconfig spamassassin on
     service spamassassin start
     check_result $? "spamassassin start failed"
+    if [ "$release" -eq '7' ]; then
+        groupadd -g 1001 spamd
+        useradd -u 1001 -g spamd -s /sbin/nologin -d \
+            /var/lib/spamassassin spamd
+        mkdir /var/lib/spamassassin
+        chown spamd:spamd /var/lib/spamassassin
+    fi
 fi