We have added a new feature to our email reporting (reports are sent via email on a daily, weekly and/or monthly basis depending on your requirements).
The new feature checks all the data whilst creating the report for any anomalies and will produce a warning message like the following.
"Note: In 100.00% of planned visits where the service was reported as working one or more monitors reported this service as being on error. The most likely cause is a configuration error preventing the monitoring servers from accessing the service being monitored. Please correct this as soon as possible."
This generally means that either your service is unreliable and not all three monitors are getting a response or that a firewall or software configuration is preventing one of the monitors from getting a response.
The message will be output when the monitor has been been reported as up for most of the period being reported on but one of the monitors is seeing an error for the majority of the time.
We have added this message to highlight the problem so that it may be resolved and allow for accurate monitoring. Generally this means you will have to resolve an issue with your service which is proving unreliable or correctly configure your firewall or software to allow our monitors to monitor your service.