Need Assistance !! While completing approval process management superbadge ,when i create 3rd approval step , i am getting this error,how to solve ?

HI @Shruti Lenka

Please log a case in Trailhead for help regarding Superbadges, they can help you better with this.

•  Super badges are part of the credentialing program,
• Please make sure you Signed up for a free org with special configuration
• Please check prerequisite.
• If not working, then log the case.  
• Please Check out the Superbadge Challenge Help article (https://trailhead.salesforce.com/help?article=Superbadge-Challenge-Help). 
• To log a case click HERE then  click "Log a Ticket"