Getting “Unexpected error occurred while inserting Opportunity records” on Trailhead Challenge – What should I do?

Hi everyone,

I'm currently working on a Trailhead challenge and running into this error message when I click on "Check Challenge":

Here’s what I’ve already checked:

• I’m using the correct Trailhead Playground
• Opportunity object is enabled and accessible
• No validation rules or required fields are blocking Opportunity creation
• No active automation (flows/triggers) on the Opportunity object

Despite this, the error still appears. 

 👉 Should I try using a fresh Playground or is there another fix?

Any help would be appreciated. Thanks in advance!