The Netdata agent monitors your HTTP endpoints. You can specify endpoints the Agent will monitor in the Agent's Go module under go.d/httpcheck.conf
.
If your system fails to connect to your endpoint, or if the request to that endpoint times out, then the Agent will mark the requests and log them as "unreachable".
The Netdata Agent calculates the ratio of these requests over the last 5 minutes. This alert is escalated to warning when the ratio is greater than 10% and then raised to critical when it is greater than 40%.
To troubleshoot this error, check the following:
Verify that your system has access to the particular endpoint.
Verify that your DNS can resolve endpoints.
Check your current DNS (for example in linux you can use the host command):
host -v <your_endpoint>
If the HTTP endpoint is suppose to be public facing endpoint, try an alternative DNS (for example Cloudflare's DNS):
host -v <your_endpoint> 1.1.1.1