Helloo..I am getting below error repeatedly. I tried all the options. Please help.

Challenge Not yet complete... here's what's wrong: 
The Lightning component named TrailheaDX must open a link to https://developer.salesforce.com/trailheadx/, must open in a new window (using the target attribute of ui:outputurl), and must be included in the Sales app.

Component code:

<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId,forceCommunity:availableForAllPageTypes,force:lightningQuickAction" access="global" >
    <ui:outputurl aura:id="TrailheaDX" value="https://developer.salesforce.com/trailheadx/" label="TrailheaDX" target="_blank" />
</aura:component>