Error 421 service not available remote server has closed connection

Hi Exchange Expert,

This morning I had an inbound mail issue. Outbound email was fine and working normal. There was intermittent inbound mail issue. No modification on exchange server configuration.

Error returned:

Error 421 service not available remote server has closed connection. Even when I tried to telnet from outside I got an error 421 4.3.2 service not available.

It started working after I adding - to receive connector -receive mail from remote servers list.

It was working fine until yesterday without specifying this IP range.

Any thoughts?


Who is Participating?
DeoraliConnect With a Mentor Author Commented:
@Simon: Exchange 201 SP3.  Thanks.  After comparing range of IPs  with the original configuration,  found out that one of the co-workers removed an IP range - 192.168.170 (pretty much this was there when I took over as Exchange admin) last night from the receive connector. Therefore, by me adding IP range might have resolved the issue.

@mnkhwaja: Not an issue with low disk space or backpressure and I mentioned above that after adding to the receive connector it started working.


Chatur Tamang
Simon Butler (Sembee)ConsultantCommented:
You must have had some kind of range in there for it to accept email.
The error you have posted is exactly what I would have expected if the range was wrong.
Furthermore it would have had that range in by default, unless it is an SBS server.

DeoraliAuthor Commented:
This is what I had before and the mail was flowing without having to add the new range -
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Simon Butler (Sembee)ConsultantCommented:
Is this an SBS Server?

Mohammed KhawajaManager - Infrastructure:  Information TechnologyCommented:
There could be two possibilities:

1. Low disk space and for more see
2. Backpressure feature and for more see
DeoraliAuthor Commented:
Please close this ticket.
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