I'm encountering the following error in the "Enable Sales Coaching in Agentforce" Trailhead unit: "We can't find the Use Sales Coach Agent permission set assigned to your user. Make sure it's not assigned to the Sales Coach Agent user."

I'm currently facing an issue while completing the Trailhead unit "Enable Sales Coaching in Agentforce." 

I’ve assigned the Manage Agentforce Sales Coach permission set to my current user, but I’m still encountering the error message:

"We can't find the Use Sales Coach Agent permission set assigned to your user." 

Can anyone please help me understand what I might be doing wrong?