When I log into the Developer Community it is a different account than what I have in the Success Community, even though the login credentials are the same. Any way to resolve this? Thanks

I'm having all sorts of problems trying to complete the challenge for the sharing rules section of this module. I feel like I have everything setup properly but still get this error message:
Challenge Not yet complete... here's what's wrong: 
The Sharing Set is not setup with proper Case access. Please check the requirements.

Sharing set name is "Share cases with customers"
Applies to Profiles: Customer Community User
Access Granted: Case - User:Account = Case:Account - Read/Write

What am I missing

 

When I log into the Developer Community it is a different account than what I have in the Success Community, even though the login credentials are the same. Any way to resolve this? Thanks