I've followed the instructions below from the 'Build an App Home Lightning Page' in trailhead and keep getting an error when I attempt to save.  The error only seems to appear because I am adding the app to the Lightning experience; however, since this is in the directions I'm not sure how to overcome it.  I've even attempted a new playground and started over but received the same error.

Link to Instructions
https://trailhead.salesforce.com/modules/lightning_app_builder/units/lightning_app_builder_apphome

Error Message: (Pops up when I attempt to activate it after adding it to the Lightning Experience apps
We had trouble processing the request. We've reported the problem to Customer Support with error ID: -406461702

Any help would be greatly appreciated!


Instructions from Link (above):
Add Your App Page to Salesforce1 and Lightning Experience
Just like the other pages, your users can’t access your app page until you activate it. During activation, you can customize the page’s custom tab label, adjust its visibility, and set its position in the Salesforce1 navigation list and Lightning Experience app navigation bars, all in one place.
Click Activation.
Don’t change the app name.
By default, the label that you give the Lightning page is used as the label for its custom tab.
Change the icon to the blue lightning bolt icon.
The icon that you choose here is used as the icon for the app in Salesforce1 and for the page in Lightning Experience.
Keep the tab’s visibility open to all users.

Tip
The Activate for the System Administrator profile only setting is useful while you’re working on your Lightning page. Restricting your page to administrators only means that you can see and test the page, but your users can’t see it until you’re ready to expose it to them.
Click the Lightning Experience tab.
Select a Lightning app, and click Add page to app.The page you’re adding to the menu appears in the second position by default. Let’s leave it there. If you put it into the top position, it becomes the landing page for all your Lightning Experience users.
Click the Salesforce1 tab.
Select the Salesforce1 Navigation Menu, and click Add page to app.
By default, new pages you add to the Salesforce1 menu appear below the Smart Search Items menu item. If you leave the Top Accounts and Opportunities page there, it will appear in the Apps section of the Salesforce1 menu. We don’t want that, so let’s move it up.
Drag the page to below the Today menu item.
Click Save.
Your app home page is now ready for your Salesforce1 and Lightning Experience users!

I've followed the instructions below from the 'Build an App Home Lightning Page' in trailhead and keep getting an error when I attempt to save.  The error only seems to appear because I am adding the app to the Lightning experience; however, since this is in the directions I'm not sure how to overcome it.  I've even attempted a new playground and started over but received the same error.

Link to Instructions
https://trailhead.salesforce.com/modules/lightning_app_builder/units/lightning_app_builder_apphome

Error Message: (Pops up when I attempt to activate it after adding it to the Lightning Experience apps
We had trouble processing the request. We've reported the problem to Customer Support with error ID: -406461702

Any help would be greatly appreciated!


Instructions from Link (above):
Add Your App Page to Salesforce1 and Lightning Experience
Just like the other pages, your users can’t access your app page until you activate it. During activation, you can customize the page’s custom tab label, adjust its visibility, and set its position in the Salesforce1 navigation list and Lightning Experience app navigation bars, all in one place.
Click Activation.
Don’t change the app name.
By default, the label that you give the Lightning page is used as the label for its custom tab.
Change the icon to the blue lightning bolt icon.
The icon that you choose here is used as the icon for the app in Salesforce1 and for the page in Lightning Experience.
Keep the tab’s visibility open to all users.

Tip
The Activate for the System Administrator profile only setting is useful while you’re working on your Lightning page. Restricting your page to administrators only means that you can see and test the page, but your users can’t see it until you’re ready to expose it to them.
Click the Lightning Experience tab.
Select a Lightning app, and click Add page to app.The page you’re adding to the menu appears in the second position by default. Let’s leave it there. If you put it into the top position, it becomes the landing page for all your Lightning Experience users.
Click the Salesforce1 tab.
Select the Salesforce1 Navigation Menu, and click Add page to app.
By default, new pages you add to the Salesforce1 menu appear below the Smart Search Items menu item. If you leave the Top Accounts and Opportunities page there, it will appear in the Apps section of the Salesforce1 menu. We don’t want that, so let’s move it up.
Drag the page to below the Today menu item.
Click Save.
Your app home page is now ready for your Salesforce1 and Lightning Experience users!