Hi,
I am getting above error while creating "New Flow"(flow builder) in my playground org or Dev org. 
There is a challange to be completed for Trailhead topic: Guide Users Through Your Business Processes with Flow Builder , where we need to create Flow. When I launch my org > navigate to Setup > Flow > and click on New flow then respective error is displayed. It also states "refreshing" page can help, but I refereshed the page several time ,still its not working.

Please help me onresolving the same , so i can complete my trailhead challenge too.

Thanks in advance.

I am unable to complete this module due to error:

Challenge Not yet complete... here's what's wrong:  The 'Calculate Discount' custom button doesn't exist or isn't properly configured. Check the instructions.

https://trailhead.salesforce.com/en/projects/flow_calculate/steps/flow_calculate_implement

I tried renaming the button API name to 'Calculate_Discount_button' as suggested in other threads. But this is not working in my DE. 

Any suggestions?
 

I am on the last module of the Build a Discount Calculator trail. I have verified the first 4 steps and received the 50 points (everything was configured correctly). Now, when I try to verify my last step I am getting the following error:

Challenge Not yet complete... here's what's wrong: 
The 'Calculate Discount' custom button doesn't exist or isn't properly configured. Check the instructions.

I've verfied the creation of the button, it's on the correct page layout and I've tested the button- it gives me the correct discount percentage and discounted amount.

Any other ideas on what I should check? I'm at a loss.