Exchange Online

Exchange Online an email provider, headquartered in Washington as part of Microsoft. It's offered by both Office 365 and Microsoft 365, providing businesses with spam filtering, block lists, and firewall protection. If a message is going to spam or getting blocked, there are typically instructions for the email admin to fix the specific error in Exchange documentation.

Jump to ↓

░█▓▓▓▓▓▓▓▓▓▓▓█▒░▒░▒░▓▓▓▓▓▓▓▓▓▒▒░▓▓▓▓▓▓▓▓▓░▓▓▓▓▓▓▓▓▓█▒▒▓█▒▒░▓▒░▒▓▓▓▓▓▓▓▓▓█▒▒▒▓░▓▓▓▓▓▓▓▓▓▓▓▓█░░░▓▓▓▓▓▓▓▓▓░▓█░▒▒░░▒▒▒▒█▒▒░▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▓▒░▒█░▓░▓▓▓▓▓▓▓▓▓▒▓▓░▒█▓▒░▒▓▓▓▓▓▓▓▓▓█▓▓▓▓▓▓▓▓▓▒▒░▓▓▓▓▓▓▓▓▓▓▓░▒░░▒█▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▓░▓▒▒░░▓░░░▓█▓▓▒▒▓▒░▓░▒▒▓░▒▒░▒░░▒▓▓▓▓▓▓▓▓▓▓▒▓▒▓▒▓▒░▓▒▒▓░▒▓▓▓▒▓░▓▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░░▓▒▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▒░░░▒█▓▓▓▓▓▓▓▓▓█▒░▓▒▓▓▓▓▓▓▓▓▓░▒▒▓▓▓▓▓▓▓▓▓░░▓▓██▓▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▒▒░▓░▓▓▓▓▓▓▓▓▓▓█▒▓█▒▒▓▒░░░▒▒▓░▒▓▓░░▒██▓░▓▓▓▓▓▓▓▓▓█░▓▓░░▒███▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓░▒█▒▓▓░▒█▓▓▒▒▒▒██░▓▓▓▓▓▓▓▓▓▒░░▓█░▒░░█▒░▓▓▓▓▓▓▓▓▓▓▒▒▓▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓█▓▓▓▓▓▓▓▓▓▒▒▒░▓░▒▓▒▓▒▒▒▒░░▓▓█░▒▓▓▓▓▓▓▓▓▓▓▒▓░▓▒▓▓░▓▓▓▓▓▓▓▓▓██▓▓▓▓▓▓▓▓▓█▒█▓▓▓░░▓█▒▓▓▓▓▓▓▓▓▓▓▓▓░▓▓▓▓▓▓▓▓▓░░▓▒▒░▓▓▓▓▓▓▓▓▓▓░▓░░▓▓▒▒█▒█▓▓▓▓▓▓▓▓▓▒▒▒▓▓▓▓▓▓▓▓▓▓▓▒▓▓▒░▒▒█▒▒▓░▒▓▒▒▓▓▓▓▓▓▓▓▓░▒░█▓▓▓▓▓▓▓▓▓█▒░▓░▒█▓▓▓▓▓▓▓▓▓▒░▓▓░▒▓▓▓█▓▒░█▒░▒▒░▓░▓▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒█▓▓▓▓▓▓▓▓▓▓█▒▒░▒▒▓▓▓▓▓▓▓▓▓▓▓▓▒▓▒░▓▒▒▒▒▒▓▓▓▓▓▓▓▓▓▒▒▓░▒▒▓▓▓▓▓▓▓▓▓░▒█░▓▓▓▓▓▓▓▓▓░▒▒▓▒░░░▒░░░▒░░▒█▓▒▓▓▓▓▓▓▓▓▓▒▒▒▒▒░▒░▓░░▓░▒░▒▓▓▓▓▓▓▓▓▓░

421All 421 codes →

smtp;421 4.3.2 The maximum number of concurrent connections per resource forest has exceeded a limit, closing transmission channel. example.com. PRX8 [example.com]

451All 451 codes →

smtp;451 4.7.0 Temporary server error. Please try again later. PRX4 NextHop: example.com [example.com]

smtp;451 4.7.500 Server busy. Please try again later from [x.xx.xx.x]. (AS77712344) [#.prod.protection.outlook.com]

550All 550 codes →

smtp;550 5.4.1 [email@example.com]: Recipient address rejected: Access denied [example.com]

smtp;550 5.7.1 Service unavailable, Client host [x.xx.xx.xx] blocked using Spamhaus. To request removal from this list see https://www.spamhaus.org/query/ip/0.0.0.0 (AS16012611)

Critical severity

550 5.7.1 Service unavailable, Helo domain is listed in Spamhaus. To request removal from this list see https://www.spamhaus.org/query/lookup/ (S8001) [#.prod.protection.outlook.com]

Critical severity

smtp;550 5.7.606 Access denied, banned sending IP [x.xx.xx.xx]. To request removal from this list please visit https://sender.office.com/ and follow the directions. For more information please go to http://go.microsoft.com/fwlink/?LinkID=526655 (AS16012609)

Critical severity

Other spam filter services

Built with

▒▒▒▒░░░░▓▓░░░█▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▓▓░▒▓▓▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▓▒▓▒▓▒▓▓▓▓▓▓▓▓▓▓█▓░░▓░░█▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒░█▒▓░▒▒▒█▓▓▓▓▓▓▓▓▓▓▓▒█▓▒█▓▓▓▓▓▓▓▓▓░▓▓▓▓▓▓▓▓▓░█▒▓░░▒▓▓▓▓▓▓▓▓▓░▒█▒░░▓▓░▓▒▒░▓▓▓▓▓▓▓▓▓▒▒▓▓█▒▓░▒▓░░░▒█░▓░▒▒░▒▓▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░█▓▒▒▒░▓▓▓▓▓▓▓▓▓█▒▓▓▒▒▒▒█▒▒▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓░░▒█▓░▒░▓█▓▒█▒▓▒▒▓▒▒░▒░▓░░▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒░▒░█▒░░▒▒▒█▓▓▓▓▓▓▓▓▓▓▒▒░▓▓▒▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▒░█▒▓▓▒▓▓▓▓▓▓▓▓▓▓░▒▒▒▓▒░░▓░▓▓▓▓▓▓▓▓▓▒▒▒▒▒▒▓░▒▓▓▒█▓▒▒▒▒▓▓░▒▒▓█▒▒░▒▒▓░▓▓▓▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▓▒▓▓▓▓▓▓▓▓▓▓▓▒▒░░▓▓▓▓▓▓▓▓▓▒▒▒▓▓▓▓▓▓▓▓▓███░░█▓▓▓░▓▓▓▒▓▒▓▓▓▓▓▓▓▓▓▒▓▒▓░░░▓░▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░▓▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▒▒▓░▒▒▒▒▒▒░▓▓▒▓▓▓▓▓▓▓▓▓░░▓▓▓▓▓▓▓▓▓░▒█▒░░▒█▓▓▓▓▓▓▓▓▓░█▓█▒▓░░░▓░▓▓▓▓▓▓▓▓▓▒▓▒░░▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓█▓█▓▓░▓▓▓░▒▓▓▓▓▓▓▓▓▓▒░▒░▒█▒▒▓▒░░▒▓▓▓▓▓▓▓▓▓▓▓░█░░▓▓▓▓▓▓▓▓▓▓░▒▒░▓▒░▓▒▒▒▓▒░▓░▒▒▒░░░░▒▓▓▓▓▓▓▓▓▓▒░▒░█▒▓▒░▓▒▒▒▒▓█▒░░░▓░▒▒▒▒▓▓▒░▒▒▒▓▓▒▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░▒░▒▓▒▒▓░▒▓▓▓▓▓▓▓▓▓▒▓▓▓▓▓▓▓▓▓▒▓▒▒▒█▒▒░█▓▓▒▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓░█▒░░█▓▓▒░░░▒█▒▓▓▓▓▓▓▓▓▓▒▒▓