I would e-mail the system administrators at that host.  It might be that
ns2.wlc.com isn't a happy "MX-er"

Ready; T=0.10/0.12 13:23:47
 dig MAILHOST.WLC.COM mx
; Ques: 1, Ans: 2, Auth: 2, Addit: 2
;; ANSWERS:
MAILHOST.WLC.COM.       86400   IN      MX      10 MAILHOST.WLC.COM.
MAILHOST.WLC.COM.       86400   IN      MX      20 ns2.wlc.com.
;; AUTHORITY RECORDS:
wlc.com.        86400   IN      NS      ns1.wlc.com.
wlc.com.        86400   IN      NS      ns2.wlc.com.


At 12:56 7/25/97 -0400, you wrote:
|Hi there!
|
|I just recieved the following error report from listserv which says:
|
|>The following 1 subscriber is currently being monitored:
|>
|>Err First Last  Address
|>--- ----- ----- -------
|>  1 07/24 07/24 xxx xxxxx <[log in to unmask]>
|>                Last error: Mailer MAILHOST.WLC.COM said: "550 not local
host
|>                            MAILHOST.WLC.COM, not a gateway"
|
|I recieved this as a daily error report from listserv (must be a new
|feature and I kind of like it), but why is this being monitored so
|quickly, when I have had delivery errors before and not recieved this kind
|of "being monitored" message?  Is it something to do with the nature of
|the error?
|
|Also, this subscriber has not had any problems before, and recently has
|been very active on the list, so this is somewhat surprising.  Shopuld I
|be a bit concerned?

How would the subscriber actually KNOW that?  99.999% don't