Check the following points if xDB doesn’t collect interaction data into collection database

1. You need have Sitecore 7.5 or later version.

2. If you are setting up Xdb in Sitecore XP 8.1 then you need to have a Sitecore license

file having xDB keys in it.

3. Check for the VisitorIdentification tag in the layout/Views

In Mvc one need add @using Sitecore.Mvc.Analytics.Extensions @Html.Sitecore().VisitorIdentification() tag, without it, it all your traffic may be treated as a 'robot' and will not get tracked.

In web form u need to add <sc:VisitorIdentification id="VisitorIdentification" runat="server" />

4. Verifying connection to the Collection Database in ConnectionString.config file using MongoDB client i.e. Open the MongoDB client and connect to the appropriate database.

To test your connection to MongoDB, do some local visits to your website. Any visits you make to your website appear as new interactions in the collection database.

Expand the analytics database and then expand the Collections node.

You can see four new collections relating to browser and system information, interaction or contact collections appear.

5. Change the session end default timeout setting from 20 to 1 minute

Open the web.config file and navigate to <sessionState> node make the changes <sessionState mode="InProc" cookieless="false" timeout="1">

Make a visit to your website test page then refresh MongoDB. Data should now appear in MongoDB after one minute.

It is highly recommended that you change the default timeout setting for testing purposes only. The default setting should be restored as soon as possible.