Hi Ralf, we have also problems sending mails to office365 hosts since tomorrow morning with both errors as you described below.
Exhibit B) Is also verified from many people here, please see " outlook.com 421 try again later S77719" . Regards, Oliver -----Ursprüngliche Nachricht----- Von: mailop <mailop-boun...@mailop.org> Im Auftrag von Ralf Hildebrandt via mailop Gesendet: Mittwoch, 11. Oktober 2023 15:15 An: mailop@mailop.org Betreff: [mailop] *.mail.protection.outlook.com reporting "452 4.5.3 Too many recipients (AS780090)" for many domains Hi! Since this morning, various MX hosts in *.mail.protection.outlook.com reporting are reporting back temporary errors for us: Exhibit A) host ohri-ca.mail.protection.outlook.com[104.47.75.228] said: 452 4.5.3 Too many recipients (AS780090) [YQBCAN01FT018.eop-CAN01.prod.protection.outlook.com 2023-10-11T02:11:41.144Z 08DBC99CDEC51952] (in reply to RCPT TO command) (for a mail with 4 recipients, in that particular case) Exhibit B) host fraport-de.mail.protection.outlook.com[52.101.73.16] said: 451 4.7.500 Server busy. Please try again later from [193.175.73.209]. (S77719) [AMS0EPF0000019E.eurprd05.prod.outlook.com 2023-10-11T01:32:21.804Z 08DBC9B278D9A989] (in reply to end of DATA command) (for a single recipient mail) This is happening for multiple tenants on *.mail.protection.outlook.com Has anybody made similar observations? According to https://sendersupport.olc.protection.outlook.com/snds/ : "All of the specified IPs have normal status." -- Ralf Hildebrandt Charité - Universitätsmedizin Berlin Geschäftsbereich IT | Abteilung Netz | Netzwerk-Administration Invalidenstraße 120/121 | D-10115 Berlin Tel. +49 30 450 570 155 ralf.hildebra...@charite.de https://www.charite.de _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop