I am partway through the Trailhead for Entitlement Management: Set Up Required Support Steps.
After I create a Milestone, I am attempting to add a time trigger under warning actions. However, when I click on Add Time Trigger, I get this error message: 
Sorry to interrupt
This page has an error. You might just need to refresh it. First, would you give us some details? (We're reporting this as error ID: )

When I x out of that error, I see this error: You don't have access to this record. Ask your administrator for help or to request access.

How can I proceed with this lesson?

I'm working through the Entitlement module attempting to add milestone actions. When I go into the Milestone and click Add time trigger under warning actions, I am taken to an error page that says:

Sorry to interrupt
This page has an error. You might just need to refresh it. First, would you give us some details? (We're reporting this as error ID: )

When I x out of the error, I get this error: You don't have access to this record. Ask your administrator for help or to request access.

How do I proceed?

Use Schema Builder to create a custom field for the Property object
DreamHouse brokers often visit properties with their clients. They want to see on the property record where the property is located. Use Schema Builder to add a street address field to the Property object.
Field data type: Text Area
Field label: Street Address
Always require a value in this field in order to save a record: Selected


Result: Challenge Not yet complete... here's what's wrong: 
The field 'Street_Address__c' either does not exists on the Property__c object or it is not of type textarea.


I have completed all the steps listed but still getting this same result. Any ideas?