When you create a RoomSketcher account using the option to sign in with Facebook, your Facebook account needs to allow sharing of your email address. 

If sharing is not allowed, you will get the following message:

How to Share Your Email Address

1. Sign in to Facebook as usual.
2. Go to Settings > Apps and websites.
3. Under Active apps and websites, tick RoomSketcher.
4. Then click on Remove.
   
   
   
   
5. Click Remove to confirm.
6. Go to www.roomsketcher.com and click on Sign Up in the upper right corner.
7. Click Sign Up with Facebook. 
8. Accept sharing your email and your RoomSketcher account is created.