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 support tickets and promises of 24-hour resolution, the block remains active.

**Error Details:**

- NDR: 550 5.7.705 Access denied, tenant has exceeded threshold

- Scope: External outbound email only is blocked; internal tenant-to-tenant email works fine

- Microsoft Defender Restricted Entities page shows 0 restricted users — the block is at tenant level, NOT user level

- No transport rules exist that could be blocking outbound

- No alerts in Exchange Admin Center

**Timeline:**

- June 19: Support ticket #2606190040005588 created, agent Manisha confirmed remediation complete and promised block would be lifted within 24 hours

- June 21 (55+ hours later): Block STILL ACTIVE. Manisha has not responded to follow-ups.

- June 21: Created 2nd ticket #2606210040000778, assigned to agent Odunayo — no action taken

- June 21: Created 3rd ticket #2606210040000844 with phone callback request — no callback received yet

**What we have tried:**

1. Three Microsoft support tickets (all Sev C)

2. Escalation emails to agent, tech lead, team manager (all bounce due to tenant block preventing outbound email)

3. Support Assistant chat bot — cannot escalate to human agents

4. Azure Portal support — No Access for this tenant tier

5. getsupport.microsoft.com — No Access

6. Microsoft Learn Q&A post: https://learn.microsoft.com/en-us/answers/questions/5926147

7. Phone callback requested on 3rd ticket — still waiting

**Critical Impact:**

The tenant cannot send ANY external email. All outbound messages to external recipients bounce with 550 5.7.705. This is a complete business email outage that has persisted for over 55 hours despite Microsoft support confirming remediation was complete.

Has anyone experienced a similar tenant-level block (550 5.7.705) that took this long to resolve? What escalation paths actually work when support agents are unresponsive? Any advice on getting this block lifted urgently would be greatly appreciated.

Cross-posted from Microsoft Learn Q&A: https://learn.microsoft.com/en-us/answers/questions/5926147