ECONNRESET after serving static file to Android device

I'm creating web app with Node, React and Koa2. I'm serving static files with koa-send module. Everything works on desktop browsers (images and mp4 videos sending fine) but on Android device there is a problem.. server sends images normaly but with mp4's i get :

  Error: read ECONNRESET
  at exports._errnoException (util.js:1050:11)
  at TCP.onread (net.js:582:26)

  Error: write ECONNRESET
  at exports._errnoException (util.js:1050:11)
  at WriteWrap.afterWrite [as oncomplete] (net.js:814:14)

  Error: write ECONNABORTED
  at exports._errnoException (util.js:1050:11)
  at Socket._writeGeneric (net.js:725:26)
  at Socket._write (net.js:744:8)
  at doWrite (_stream_writable.js:329:12)
  at writeOrBuffer (_stream_writable.js:315:5)
  at Socket.Writable.write (_stream_writable.js:241:11)
  at Socket.write (net.js:671:40)
  at ServerResponse._writeRaw (_http_outgoing.js:177:23)
  at ServerResponse._send (_http_outgoing.js:150:15)
  at ServerResponse.write (_http_outgoing.js:536:16)

..and there is nothing playing inside video tag.

My main app file:

      /*jshint esversion: 6 */
      /*jslint node: true */
      'use strict';

      import Koa from 'koa';
      import Router from 'koa-router';
      import send from 'koa-send';

      require("babel-polyfill");

      const app = new Koa();
      const router = new Router();

      /*jshint ignore: start */
      router
        .get('/', async (ctx, next) => {
          console.log('sending main...');
          try {
            await send(ctx, '/main.html', { root: __dirname });
          } catch (error) {
            console.log('error in / : ' + error);
            ctx.body = '<h1>Ooops... something is wrong !';
          }
        })
        .get('/app.js', (ctx, next) => {
          ctx.redirect('/');
        })
        .get('/main.html', (ctx, next) => {
          ctx.redirect('/');
        });

      app
        .use(async (ctx, next) => {
          await next();
          console.log('status: ' + ctx.status);
        })
        .use(router.routes())
        .use(router.allowedMethods())
        .use(async (ctx) => {
          try {
            await send(ctx, ctx.path, { root: __dirname });
            console.log('sending file: ' + ctx.path);
          } catch (error) {
            console.log('error:: no file at: ' + ctx.path);
            ctx.redirect('/');
          }
        })

      /*jshint ignore: end */

      app.listen(process.env.PORT || 3000);

a code fragment that's creating video tag (react):

            <video
                controls={false}
                loop
                autoPlay
                src={this.props.gifPath}
                onCanPlayThrough={() => this.props.loadHandler(this.props.gifPath, true)}
            />