I signed up for a Developer Edition previously, so when starting this Trailhead, I logged into it and followed the instructions.

One of the early instructions is to install Agile Accelerator from the AppExchange.  I can go there and select it, but when trying to install, the instructions in the Trailhead say "At this stage, you’ll be asked whether you want to install it in a sandbox or in production."  However after pressing "Get it Now", I get an error message that says:

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Oops! Looks like you don't have permission to install apps.

To keep your Salesforce secure, only system administrators have permission to install apps or components. Please contact your Salesforce system administrator to install this app or component.

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I have checked my user in my DE account and it shows that my user is a System Administrator.

My username is: jpayne@trailhead.com

So I can't continue with the Trailhead.

Can you help?

I signed up for a Developer Edition previously, so when starting this Trailhead, I logged into it and followed the instructions.

One of the early instructions is to install Agile Accelerator from the AppExchange.  I can go there and select it, but when trying to install, the instructions in the Trailhead say "At this stage, you’ll be asked whether you want to install it in a sandbox or in production."  However after pressing "Get it Now", I get an error message that says:

--------------------------------------------

Oops! Looks like you don't have permission to install apps.

To keep your Salesforce secure, only system administrators have permission to install apps or components. Please contact your Salesforce system administrator to install this app or component.

--------------------------------------------

I have checked my user in my DE account and it shows that my user is a System Administrator.

My username is: jpayne@trailhead.com

So I can't continue with the Trailhead.

Can you help?