com.facebook.react.bridge.readablenativemap cannot be cast to java.lang.string

Why do I get the error with my code :

            RNFetchBlob.config({fileCache: true}).fetch("https://gateway-lon.watsonplatform.net/text-to-speech/api/v1/synthesize?accept=audio%2Fwav&text=hola%20mundo&voice=es-ES_EnriqueVoice",
            {
                method: 'GET',
                headers: {
                    'Authorization': 'Basic ' + btoa('apikey:my_api_key_here'),
                }
            })
            .then(
            (res) =>  console.log('response has arrived'),
            (error) => console.log('ERROR OCCURED', error)
            )

• “react”: “16.9.0”
• “react-native”: “^0.61.0”
• “rn-fetch-blob”: “^0.11.2”

[vitto-moz]

in my case, there was needed to stringify body

RNFetchBlob.fetch(
      config.method || DEFAULT_CONFIG.method,
      config.url,
      {Authorization: token, ...DEFAULT_CONFIG.headers},
      JSON.stringify(config.body) // <==== here
    )

[hungdev]

in my case, there was needed to stringify body

RNFetchBlob.fetch(
      config.method || DEFAULT_CONFIG.method,
      config.url,
      {Authorization: token, ...DEFAULT_CONFIG.headers},
      JSON.stringify(config.body) // <==== here
    )

Thank you so much!. It worked ❤️