What is this error code? Pingdom Detailed Check API "/tms/check/{checkid}/report/status" returned: Status of "Unknown", with message of "Internal test error. Error code: 42004"

This may help others.  This information is directly from Pingdom support:  Status of "Unknown" is what Pingdom's probe servers show when they do not have a status for whatever the reason. And Pingdom does *not* notify you of this.  Instead you would only know if you went to your my.Pingdom account and checked the status.

Now to clarify, this 'Unknown" status is what showed along with this post's title, where Pingdom was showing a message of "Internal test error." 

To me, there are 3 big problems with this:

1.  When reviewing status history, "Unknown" appears many times, mostly in 10 min increments (not a big deal) - but I ran across several that last for several hours (ex 11 hours), and in one case, over 4 days.

2.  You could potentially be thinking you have no issues when in reality your site is down and you'd have no idea unless you checked my.Pingdom constantly, or worse, you hear it from your users

3.  Integrating Pingdom with StatusPage could be very counter-productive, since StatusPage only updates upon receiving a notification from Pingdom.  And if this "unknown" status is prolonged, which in one of my cases lasted *over* 4 days, StatusPage could be showing a misleading status.

Don't get me wrong - I think Pingdom has a pretty good setup and I like the general user experience.  My issue is how the "Unknown" status is being handled.  Fix this, along with the max test timeout of 60 seconds (more like 3 minutes would be ideal) then you'd have a perfect status notification tool.

This may help others.  This information is directly from Pingdom support:  Status of "Unknown" is what Pingdom's probe servers show when they do not have a status for whatever the reason. And Pingdom does *not* notify you of this.  Instead you would only know if you went to your my.Pingdom account and checked the status.

Now to clarify, this 'Unknown" status is what showed along with this post's title, where Pingdom was showing a message of "Internal test error." 

To me, there are 3 big problems with this:

1.  When reviewing status history, "Unknown" appears many times, mostly in 10 min increments (not a big deal) - but I ran across several that last for several hours (ex 11 hours), and in one case, over 4 days.

2.  You could potentially be thinking you have no issues when in reality your site is down and you'd have no idea unless you checked my.Pingdom constantly, or worse, you hear it from your users

3.  Integrating Pingdom with StatusPage could be very counter-productive, since StatusPage only updates upon receiving a notification from Pingdom.  And if this "unknown" status is prolonged, which in one of my cases lasted *over* 4 days, StatusPage could be showing a misleading status.

Don't get me wrong - I think Pingdom has a pretty good setup and I like the general user experience.  My issue is how the "Unknown" status is being handled.  Fix this, along with the max test timeout of 60 seconds (more like 3 minutes would be ideal) then you'd have a perfect status notification tool.