@Ali Alizada The text translator services uses content type JSON where the text elements need to be document elements as key "Text" values. In your case you are trying to translate an entire JSON which is not possible unless you pre-process your document and pass each value in your document as mentioned in above format.
Even, the document translation feature does not support the JSON format. You will have to convert your JSON doc to a txt document and pass the same to document translation service to achieve the translated output.
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