Okay, so I started out using the Membership provider (the methods on Member are marked obsolete), doing this:

            MembershipUser user = Membership.Provider.CreateUser(username, password, emailAddress, string.Empty, string.Empty, true, null, out status);

It worked nicely. Now all of a suddent it doesn't. A small note, the username is the same as the e-mail address.

Now I can try with whatever e-mail address I want, but I always get a "member already exists". Obviously it doesn't.

So to try and fix it, I went back to the old code,

            if (Member.GetMemberFromLoginName(username) == null) {
                if (Member.GetMemberFromEmail(emailAddress) == null) {
                    MemberType memberType = MemberType.GetByAlias("ForumMedlem");
                    Member member = Member.MakeNew(username, emailAddress, memberType, User.GetUser(0));
                    member.Password = password;
                    member.Save(); 
                }
            }

But exactly same problem.

I can create the member fine in the back-office.

Any ideas? Any at all? Well, apart from upgrading the site to the latest.

Thanks, Steen