By default the logs are sent to stderr. Common errors in the logs include missing APPOPTICS_SERVICE_KEY and not having been installed with the native library bindings built (should happen automatically on most platforms).
You can check if your application is correctly instrumented by looking for X-Trace headers, eg. using curl:
curl -i http://the-url-of-your-website HTTP/1.1 200 OK ... X-Trace: 2BB5CEC860E76D82425C8048BBF5469BE9BC580A628B4A5611C2CA3A5601
You will find the HTTP header
X-Trace from the HTTP response if the instrumentation is installed and enabled.
As a second diagnostic, the last two characters of
X-Trace header indicates whether the request is traced:
it is traced if the last two characters are
01 while not traced if they are
00. It is not expected that all requests will be traced; in high-traffic environments, automatic sampling kicks in.
Enable the verbose logging by define the following environment variable to 6 (Please don’t enable it in production environment as it will flood your system with verbose logs):
See logging level for more information.
Review the agent log messages to see if there are any connection issues logged.
If your server is behind a firewall, please see the FAQ: My application is behind a firewall. What IP address(es) do I need to whitelist?.