cPanel does not update SpamAssassin
Looks like a fresh installed cPanel has an outdated SpamAssassin rules that mark legitimate emails as spam. There are 2 obsolate rules: DNS_FROM_OPENWHOIS and FH_DATE_PAST_20XX
Try search /var/log/maillog for these rules. If found, you need to run sa-update
# grep -l DNS_FROM_OPENWHOIS /var/log/maillog
/var/log/maillog
shorturl: