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 be related to the "sleep" function, as I had added a "sleep" step for 15 seconds before this error came up.

Having said that, there is no reference in the solarwinds documentation that refers to any error codes returning in the Pingdom API report status call, no less an error code of 42004.

Thanks in advance.

James