Rejection of some emails due to SPAM

Hi. Rejection of some emails due to SPAM Emails are rejected with the following message: Jan 6 16:17:25 postfix-inbound-4 postfix / smtp [16685]: 23A7440285: to = , relay = domain.com [x.x.x.x]: 25, delay = 45, delays = 0.12 / 0/21/25, dsn = 5.0.0, status = bounced (host domain.com [x.x.x.x] said: 550 This message was classified as SPAM and may not be delivered (in reply to end of DATA command)) We have reviewed and cannot find what is blocked Is it possible to whitelist the sender for the whole server? Thank you