Error Logs?

I have been testing xymon to replace the big-brother system.  Some time
during the additions and deletions I seem to have messed up something
because the status pages no longer update and the service links fail
with errors like:

Cannot load host configuration

or

The requested URL /xymon-cgi/30 was not found on this server.

I've tried the obvious thinks like restarting xymon and apache.

Is there an error log or logs I can look at to find out why?

server: CentOS7 - 7.3.1611
 xymon: 4.3.28
 httpd: 2.4.6