Member Avatar for jus learnin

I'm running netscape 7.1 on XP. Have not been able to successfully send mail to persons with hotmail addresses for the past 3 days. Preferences are set to enable all cookies.

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This thread documents a common delivery problem: the mail client looks fine but Hotmail/Outlook rejects outbound messages because the sender’s IP or network is blocked upstream. Contacting the ISP (as suggested and later confirmed) is often the decisive step — many Hotmail/Outlook bounces that show a 5.7.x error reference a network-level block (examples commonly appear as “S3150” or similar). (learn.microsoft.com)

Practical troubleshooting steps that apply to this and future similar cases:

  • Save the full non-delivery report (NDR) and message headers; the SMTP reply line (for example: 550 5.7.1 or 554 5.7.1) is the key diagnostic. RFC 5321 explains the meaning of 4xx vs 5xx SMTP replies (temporary vs permanent). (ietf.org)
  • Verify the outgoing SMTP server configured in the client (use the ISP’s SMTP, confirm SMTP authentication is enabled, and check port — port 25 is commonly blocked by some networks; try 587 if supported).
  • Test connectivity and server responses with a simple telnet session to the ISP SMTP host and issue EHLO/MAIL/RCPT to see the server’s immediate rejection text:
telnet smtp.your-isp.example 25
EHLO example.com
MAIL FROM:<sender@example.com>
RCPT TO:<recipient@hotmail.com>

If the RCPT or MAIL command returns a 5.x.x rejection, that text is what the ISP (or Microsoft) needs to investigate. (ietf.org)

When the bounce explicitly mentions a block or S3150, the ISP must investigate and — if appropriate — use Microsoft’s sender/postmaster/delist channels (postmaster/SNDS/delist portals) to resolve reputation or network-level blocks. Microsoft’s documentation and community guidance explain the delisting/support routes and how to interpret NDR text. For persistent S3150-style errors, insist that the ISP open the postmaster/delist process with Microsoft and provide the full bounce text. (learn.microsoft.com)

A few quick workarounds while the ISP follows up: send via a different network (mobile hotspot), use a different authenticated SMTP provider, or send via webmail — these prove whether the problem is tied to the ISP network. ’s suggestion to check client docs helps for client settings, but when the server’s NDR shows a provider block, the fix must come from the ISP or Microsoft. (learn.microsoft.com)

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Member Avatar for caperjack

I would check Netscape help and see if you can find any info on others haveing the same problems .

Member Avatar for DMR

Is it just Netscape, or does this happen with Internet Explorer as well?
Does it seem to be only hotmail recipients?
Can you send mail to the recipients from another computer?

You might want to contact your ISP; it could be a problem with something "upstream".

Member Avatar for jus learnin

I would check Netscape help and see if you can find any info on others haveing the same problems .

Checked netscape help, but did not find a solution

Member Avatar for DMR

As I suggested, also contact your ISP.

Member Avatar for jus learnin

Thanks,
I have spoken with my ISP and they have confirmed that this is a problem related to them which they are currently working on a fix for. Thanks alot for the pointer.

Member Avatar for DMR

Thanks,
I have spoken with my ISP and they have confirmed that this is a problem related to them which they are currently working on a fix for. Thanks alot for the pointer.

You're welcome.
I hope they get it sorted out for you soon. :)

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