4.7.500–4.7.699: Access denied, please try again later
Microsoft returns a code between 4.7.500 and 4.7.699 (or 4.7.850 to 4.7.899 for an IP) when it detects suspicious activity and temporarily restricts sending while it evaluates. If the traffic is legitimate, Microsoft says the restriction lifts shortly. Slow down; do not hammer retries.
The exact messages
Microsoft 365 / Exchange Online
4.7.500-699 Access denied, please try again later
Microsoft 365 / Exchange Online
4.7.850-899 Access denied, please try again later
Why it happens
- A burst of mail from a new IP, domain or tenant.
- Content or behaviour that looks like spam to Microsoft’s filters.
How to fix it
- Let the server retry on its normal schedule, and pause any new volume.
- Lower per-mailbox sending rates once mail flows again.
- If it persists for days, check the IP against blocklists and Microsoft’s delist portal.
If you send cold email
This is Microsoft’s early warning before a ban such as 5.7.606 or 5.7.708. Treat it as a signal to cut volume on that mailbox or IP now.
How WarmHawk handles it
WarmHawk pauses a mailbox on its own once its hard-bounce rate passes 5% over at least 20 sends, and pauses a campaign at that campaign’s own bounce threshold, so a bad list stops before it drags the domain down. Every sending domain is re-checked against DNS blocklists hourly, and a mailbox only reaches campaign volume after at least 14 days of warmup with a 90% inbox rate. A mailbox whose inbox rate falls below 70% goes back to warmup. How WarmHawk works →
Check your domain now
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Related bounce codes
- 5.7.606Access denied, banned sending IP
- 5.7.708Access denied, traffic not accepted from this IP
- 4.7.0Temporarily deferred: low reputation, PTR or TLS
Sources, checked 2026-09-29: Microsoft Learn: NDRs and SMTP errors in Exchange Online. Have a different bounce? Paste it into the decoder →
Questions
4.7.500 questions
What does 4.7.500 mean?+
Microsoft returns a code between 4.7.500 and 4.7.699 (or 4.7.850 to 4.7.899 for an IP) when it detects suspicious activity and temporarily restricts sending while it evaluates. If the traffic is legitimate, Microsoft says the restriction lifts shortly. Slow down; do not hammer retries.
Is 4.7.500 a temporary or permanent error?+
Temporary. The sending server keeps the message and retries it for a while. It only becomes a bounce if every retry fails before the message expires.
How do I fix 4.7.500?+
Let the server retry on its normal schedule, and pause any new volume. Lower per-mailbox sending rates once mail flows again. If it persists for days, check the IP against blocklists and Microsoft’s delist portal.