One client alerts and a (seemingly) identical client doesn't.

I have two servers being monitored, a specific log file is monitored
on each and the alerts, client-local and analysis file entries are
identical for each.  And yet one works (shows a reg MSGS dot and sends
an e-mail) and one doesn't.  It did for a while and then stopped.  I
have restarted xymon client on the server to no avail.

What tools ara available and what should I be looking for in order to
solve this peculiar problem?

Regards,

Nick Pettefar