Your Scouts.org.uk account uses your email address as your login (instead of having a separate username like Compass.)
Because more than one person has the same login, then the system doesn't know which person it's talking to.
As a result, you can't activate or reset your account password.
We're afraid that this issue can only be resolved by contacting the HQ Support Team and letting them know which personal email addresses you'd like to use for logging in.