Another possibility would be an issue with the document itself. Consider attempting to resolve it by implementing a selection box to crop a specific region within the image. Alternatively, you may also try using a different image file to see if the problem persists.
How to install new languages for OCR detection?
OCR Reader utilizes Tesseract engine which supports more than 100 languages. In order to install new OCR languages, go to https://github.com/tesseract-ocr/tessdata and download the trained data file for your language. Then, copy the .traineddata file to the proper location like C:\Users\[USERNAME]\AppData\Roaming\VOVSOFT\OCR Reader\tesseract\tessdata.