Microsoft 550 SC-004: blocked on complaints
Microsoft / Outlookreputation_blockaction: pause
550 SC-004 means Microsoft has placed a block on your address after receiving complaints about mail from it. Unlike SC-001, this one names its cause, and Microsoft's own remedy is to enrol in the Junk Email Reporting Program.
Microsoft publishes no complaint threshold, so there is no figure to stay under. The colour bands in SNDS do not help either: they report how much of your mail the filter classified as spam, not how often it was reported, which is the fact most often repeated wrongly about this.
What it looks like in the log
550 SC-004 Mail rejected by Outlook.com for policy reasonsWhy it happens
- Recipients marking the mail as junk at a rate Microsoft acts on.
- A list segment that was never engaged, or addresses acquired rather than collected.
What to do
- Stop sending to Microsoft domains from this address until the cause is removed. Continuing deepens the block.
- Enrol in JMRP, which is what Microsoft names in the refusal, so complaints arrive as feedback rather than only as a block.
- Suppress everyone who complained, then cut to recipients who opened something recently before resuming.
- Submit a delisting request only after the cause is fixed.
Related
Blocklist check checks whether the address is listed elsewhere as well, since the complaints behind this rarely stop at one receiver. Open blocklist check