Quite a few users keep getting a message saying their e-mail did not reach the intended
recipients, and also that there was a communication error and the sender has been
Could you explain this?
There are a number of reasons why e-mail might get bounced back, but since your
message specifies a "communication error" I'll touch on that aspect.
Usually that error is due to either a service outage on your end or on theirs (i.e., your
connection (or theirs) is down).
You might also see that message (though it might specify "host unreachable") if the
domain name of their address is incorrect ("microsfot.com" for example) or if it can't be
located in DNS, because your DNS settings are incorrect, the DNS server is down, or
their domain is not properly registered.
If it's happening to "quite a few users," the problem sounds pretty pervasive so I'd start by
making sure that you have proper DNS settings and that the DNS server(s) you're using is