Hi, Microsoft are tracking this as EX1467029 in their admin center.
Active incident. Graeme -----Original Message----- From: mailop <[email protected]> On Behalf Of Alessio Cecchi via mailop Sent: Friday, September 4, 2026 10:40 PM To: [email protected] Subject: Re: [mailop] Limited deliverability to M365 Hi, here in Italy, we (Qboxmail) and other ISPs are having the same problem. We're getting errors: 451 4.7.500 Server busy with codes: S77714 S77717 S77719 The problem started at 9:47 CEST on all our IPs at once. Microsoft reports an incident (Delays or failures when sending or receiving email messages) that has been resolved, but apparently not completely: https://admin.microsoft.com/Adminportal/Home#/servicehealth/history/:/alerts/EX1464935 It seems that messages are still arriving from US-based ISPs. We've filed reports with Microsoft, but for now, the problem persists. Any suggestions? Il 04/09/2026 11:31, lukn via mailop ha scritto: > Hello Mailops > > A few hours ago Microsoft suddenly started to drastically rate limit > all our servers with the following message: > > > 451 4.7.500 Server busy. Please try again later from [x.x.x.x]. (S7 > 7719) > > Is anyone else affected? Problem on their or our side? (Downdetector > for some European countries hints towards Redmond...) > > Best regards > lukn > _______________________________________________ > mailop mailing list > [email protected] > https://list.mailop.org/listinfo/mailop -- Alessio Cecchi postmaster AT qboxmail https://it.linkedin.com/in/alessice _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
