I get response that has incorrect TYPE of value for parameter ErrorMessage.
Free OCR API - Response states it should be TEXT, however I get COLLECTION, here sample:
{"ParsedResults":[],"OCRExitCode":6,"IsErroredOnProcessing":true,"ErrorMessage":["Timed out waiting for results"],"ProcessingTimeInMilliseconds":"7548"}
According to your docs, this rather should be:
{"ParsedResults":[],"OCRExitCode":6,"IsErroredOnProcessing":true,"ErrorMessage":"Timed out waiting for results","ProcessingTimeInMilliseconds":"7548"}