Forum Discussion
DennisRS
Jun 21, 2026Copper Contributor
550 5.7.705 Tenant Email Block 55+ Hours - Support Unresolved
Our M365 tenant (labaradorpake.onmicrosoft.com) has been blocked from sending outbound email for over 55 hours with error 550 5.7.705 Access denied, tenant has exceeded threshold. Despite multiple su...
Jun 23, 2026
DennisRS​ Are you trying to send mail from your onmicrosoft.com domain or is this happening with a custom/vanity domain? If it is your onmicrosoft.com domain, then see Limiting Onmicrosoft Domain Usage for Sending Emails | Microsoft Community Hub, which explains how and why Microsoft limits messages from MOERA domains.