I received this error. I created the requirements in the dev org I have used on all of my past modules and a new one I created. I create quite a few reports and am very comfortable working with them. 

Step Not yet complete... here's what's wrong: 
There was an unexpected error while verifying this challenge. Usually this is due to some pre-existing configuration or code in the challenge Org. We recommend using a new Developer Edition (DE) to check this challenge. If you're using a new DE and seeing this error, please post to the developer forums and reference error id: MDTHCXOI 

I am having a hard time on this one. The error I keep getting is  'Challenge not yet complete... here's what's wrong: 
The 'Phone__x' external object is not correctly setup with an indirect relationship to the User standard object.'

I followed the steps carefully and the Phone__x external object is setup with an indirect relationship to the User standard object. 

Any help would be very appreciated.

I need all my leads to show what time zone they are in. I created a formula that takes their phone numbers area code and automatically shows their time zone. My issue is that I recently synced leads from pardot and the phone number format is different. The synced leads are showing as 1.235.524.5641 whereas the previous leads I have are in the format 2545856589. Is there a way that I can get these new leads to change the format of their phone numbers? Or possibly update my code to allow this new format to match to their corresponding time zones?
Thanks!

Here is the current formula I have. 

Data Type Formula    
if( ISBLANK(Phone),"--", 

if(CONTAINS("206:209:213:253:310:323:360:408:415:425:503:509:510:530:559:562:604:619:626:650:661:702:707:714:760:775:778:805:818:831:858:867:909:916:925:949:951:971:236:250:604:778:867", left(SUBSTITUTE( Phone , "(", ""),3)),"UTC-8 Pacific", 

if( CONTAINS("208:250:303:307:385403:406:435:480:505:520:602:623:719:720:780:801:928:970:403:587:780", left(SUBSTITUTE( Phone , "(", ""),3)),"UTC-7 Mountain", 

if( 
CONTAINS("204:205:210:214:217:218:224:225:228:251:254:256:262:270:281:306:308:309:312:314:316:318:319:320:325:334:337:361:402:405:409:414:417:430:432:469:479:501:504:507:512:515:563:573:580:601:605:608:612:615:618:620:630:636:641:651:660:662:682:708:712:713:715:731:763:769:773:785:806:815:816:817:830:832:847:901:903:913:915:918:920:931:936:940:952:956:972:979:985:204:306:431:639:807", left(SUBSTITUTE( Phone , "(", ""),3)),"UTC-6 Central", 

if(CONTAINS("201:202:203:207:212:215:216:219:226:229:231:234:239:240:248:252:267:269:276:289:301:302:304:305:313:315:321:330:336:339:345:347:351:352:386:404:407:410:412:416:418:419:434:438:440:443:450:470:475:478:484:502:508:513:514:516:517:518:519:540:551:561:567:570:571:585:586:603:606:607:609:610:613:614:616:617:631:646:647:649:678:703:704:705:706:716:717:718:724:727:732:734:740:754:757:770:772:774:781:786:802:803:804:810:813:814:819:828:835:843:845:848:856:857:859:860:862:863:864:865:876:878:904:905:908:910:912:914:917:919:937:941:947:954:959:973:978:980:226:249:289:343:365:416:437:438:450:514:519:579:581:613:647:705:819:873:905", left(SUBSTITUTE( Phone , "(", ""),3)),"UTC-5 Eastern", 

if( CONTAINS("506:709:902",LEFT(SUBSTITUTE(Phone,"(",""),3)),"UTC-4 Atlantic", 

if( CONTAINS("800:877",LEFT(SUBSTITUTE(Phone,"(",""),3)),"Toll Free","Other" 
)))))))

I received this error. I created the requirements in the dev org I have used on all of my past modules and a new one I created. I create quite a few reports and am very comfortable working with them. 

Step Not yet complete... here's what's wrong: 
There was an unexpected error while verifying this challenge. Usually this is due to some pre-existing configuration or code in the challenge Org. We recommend using a new Developer Edition (DE) to check this challenge. If you're using a new DE and seeing this error, please post to the developer forums and reference error id: MDTHCXOI 

I've tried logging into Trailhead and it will allow me to log in but it won't let me undertake any challenges it keeps saying log into developer edition.  When I try to sign up again it says that I'm already logged in.  Please can someone tell me how to log into the developer edition.  Thank you.
 

Hello I'm new to Salesforce and I'm doing the trailhead to learn.
But I'm stuck at this challenge in Lightning Module.

Here's the challenge:
Create a simple Lightning component with a styled headline. The headline must use an H1 tag with a CSS class that enforces a 24px font-size. Make the component available in the Navigation Menu of Salesforce1.The component must be named 'MyLightningComponent'.
The component must include an H1 tag with a CSS class named 'headline'. The 'headline' CSS class must set a font-size of 24px.
The Lightning Component tab that is added to Salesforce1 must be called 'MyLightning'.

And here's what I did:

MyLightningComponent.cmp

<aura:component implements='force:appHostable'>
    <div class="headline">
    <h1>My Lightning Component</h1>
    </div>
</aura:component>

MyLightningComponentApp.app

<aura:application>
    <h1>Hello Lightning App!</h1>
    <c:MyLightningComponent />
</aura:application>

MyLightningComponent.css

.THIS {
}

.THIS.headline{
    font-size:24px;
}

I created the tabs in the Salesforce1 and everithing looks right but I can't pass the challenge because it's aways return a error saying "The component does not include an H1 tag with a 'headline' CSS class"

I do no what to do with this error.

The challenge is:

You've been given a requirement to keep Contact addresses in sync with the Account they belong to. Use Process Builder to create a new process that updates all child Contact addresses when the address of the Account record is updated. This process:Can have any name.
Must be activated.
Must update Contact mailing address fields (Street, City, State, Post Code, Country) when the parent Account shipping address field values are updated.

I start with Accounts when records is created or edited.
Filter criteria where accounts shipping address (street, city, state, zip code) is changed (used "or" logic).

I am stuck on the next step "add action".  I started with action type "Update Records".
On objects, I can't seem to change Accounts to Contacts.  Why?

Help please - I am trying to complete the Lightning Challenge here:

https://developer.salesforce.com/trailhead/lightning_components/lightning_components_creating

But when I submit I am told it is wrong:

The component does not include an H1 tag with a 'headline' CSS class

My component reads:

<!-- MyLightningComponent.cmp -->
<aura:component implements="force:appHostable"> 
    <div class="headline">
        <H1>Hello Lightning Component!</H1>
    </div>    
</aura:component>

and I have a Style:

.THIS {
    background-color: yellow;
    padding-top: 10px;
}

H1.THIS {
    font-size:24px;
}

.THIS H1{
    font-weight: bold;
    padding: 10px;
}

.THIS.headline {
    padding-top: 20px;
    font-size:24px;
}

.THIS .red {
    background-color: red;
    padding: 10px;
}

.THIS .blue {
    background-color: blue;
    padding: 10px;
}

.THIS .green {
    background-color: green;
    padding: 10px;
}

Can anyone describe what I have done wrong?