What the receiver is telling you
Microsoft's throttle on an IP whose reputation is uncertain or slipping. The IP is not banned; Microsoft is accepting less from it while it evaluates. New dedicated IPs get this during warmup, and established IPs get it after a spike in complaints or bounces. Retries go through at a reduced rate. It is the Microsoft counterpart of Gmail's 4.7.28 and the warning before 5.7.708 or 5.7.606.
How to handle a soft bounce
Your server or sending tool retries soft failures automatically, usually for one to three days. Most clear on their own. The mistake is leaving an address that soft-bounces on every step in an active sequence: each attempt is logged, and a mailbox that has been full or unreachable for two weeks is not going to read a follow-up. Three consecutive soft failures is the point to remove it. Track soft bounces separately from hard ones; they are a different signal and receivers weight them differently.
What to do
- Slow down to Microsoft-hosted recipients — Outlook.com and 365 tenants — for a few days.
- Check that the IP has forward-confirmed reverse DNS and that every domain sending through it authenticates.
- If it is a new IP, warm it: small volumes to engaged recipients first.
- If it is an old IP that suddenly got this, look for a compromised inbox or a bad list on the same IP.
don't Do not open a delisting request for a 4.7.650. It is not a listing, and the request will be declined.
Decode the whole bounce
Paste the complete failure notice — every code and the receiver's wording — and get each part explained together.
Common questions
Is 4.7.650 a block?
No. Mail is delayed and delivered at a lower rate. It becomes a block if the reputation keeps falling.
How long does it last?
Days, typically. It clears as Microsoft sees consistent, low-complaint volume from the IP.
Often seen alongside
Related reading
If this is the thing going wrong
The pages explain it. If you would rather it was simply fixed, that is the work I do.