Shape Files not showing in OpenLayers using QGIS export to OpennLayers 3 plugin

I am new to GISs in general and I am working with QGIS to generate layers to be shown on OSM using OpenLayers.

My problem is the following:

I have multiple layers in a QGIS project and I want to export all of them to be displayed in OpenLayers. To do that I used two methods:

1) Export to OpenLayers 3 plugin of QGIS

The exporting process is done without errors but when I try to visualize some layers they don't appear even when I hide the rest of the layers including the base OSM layer.

2) js-shapefile-to-geojson javascript API

This API converts shape files to geojson format but projecting them on an OSM map doesn't place them correctly.

They appear like a dot in a placement too far from the desired location. However, when I tried to visualize the same layers that does not appear using the test page provided by the API I was able to visualize them. So here the problem is to integrate the layers with OSM.

Are there any suggestions on how to visualize these layers using QGIS plugin ?