I'm using multers3 and nestjs to perform file uploading and some further processing to which I'm getting error

Question

I need to perform the processing (in async upload) after the file has been uploaded, to which I'm getting error. At first I was using diskStorage instead of cloud to which my code was running correctly.

   //Initial code that saved files to disk
    @UseInterceptors(FileInterceptor('file', {
    storage: diskStorage({
    destination: './uploads', filename: (req, file, cb) => {
    const randomName = Array(32).fill(null).map(() => (Math.round(Math.random() * 16)).toString(16)).join('')
    cb(null, `${randomName}${extname(file.originalname)}`)
    }
    })
    }))

    //changed code which stores file to cloud
    @UseInterceptors(FileInterceptor('file', {
    storage: multerS3({
    s3: s3,
    bucket: 'uploads',
    key: function (req, file, cb) {
    console.log(file);
    cb(null, file.originalname); //use Date.now() for unique file keys
    }
    })
    }))

    //the further processing reqd 
    async upload( @UploadedFile() file){
    try {
    ...somecode
    }
    catch (error) {
    throw new Error(error);
    }
    }

It gives error, "Error: File does not exist. Check to make sure the file path to your csv is correct." What could be the possible reason?