Dear Kebba, my guess is, that lighttec.com.eg have a misconfigured SPF record. (IF (!) they use Google services for their mail !) TXT record -> "v=spf1 +a +mx +ip4:213.158.187.39 +ip4:213.158.187.0/24 -all" So Google (with mail-wm0-f52.google.com [74.125.82.52] ) is sending on behalf of lighttec.com.eg which is not included in their SPF record, so your mail server is telling you, that something is wrong here and blocks it. So: might be SPAM, might be misconfiguration on lighttec.com.eg side. But your config is OK. Kind regards, Michael Seidel Systemadministrator FAI rent-a-jet AG http://www.fai.ag/ -----Ursprüngliche Nachricht----- Von: users [mailto:users-bounces(a)exim4u.org] Im Auftrag von Kebba Foon Gesendet: Montag, 1. Februar 2016 13:06 An: users(a)exim4u.org Betreff: [Exim4U] Not authorized by SPF Dear list, Am receiving below error for this particular user, i don't understand why spf is rejecting this address or how to white-list it from spf check: 2016-02-01 10:38:47 H=mail-wm0-f52.google.com [74.125.82.52] F=<hamada_hegazy(a)lighttec.com.eg<mailto:hamada_hegazy(a)lighttec.com.eg>> rejected RCPT <********@qcell.gm<mailto:********@qcell.gm>>: Sender address not permitted - SPF.: Not authorized by SPF _______________________________________________ users mailing list users(a)exim4u.org<mailto:users(a)exim4u.org> https://exim4u.org/mailman/listinfo/users