Question

MembershipService.ChangePassword doesn’t change password issue. I have no clue why…

var userUsers = from n in db.aspnet_Users where n.UserId == id select n;
                string userName = userUsers.Single<aspnet_Users>().UserName;

                MembershipUser user = Membership.GetUser(userName, false);
                if (user != null)
                {
                    string generatedPassword = user.ResetPassword();
                    if (MembershipService.ChangePassword(userName, generatedPassword, model.NewPassword))
                    {   

// So it doesn't change the password

Answer 1

Check this out in the documentation:

ChangePassword returns true if the password was updated successfully.
Otherwise, it returns false.

Before changing a password, ChangePassword calls the provider’s overridable OnValidatingPassword method to validate the new password. It then changes the password or cancels the action based on the outcome of the call.

If the user name, password, new password, or password answer is not
valid, ChangePassword does not throw an exception; it simply returns
false.

Following a successful password change, ChangePassword updates the user’s LastPasswordChangedDate.

This helped me once when I had the exact same problem. The password was not valid so the method never actually changed it. I changed some password configuration in the web.config file and then it finally worked.

Check this lines of your web.config, this might be the problem:

<membership defaultProvider="Demo_MemberShipProvider">
    <providers>
       <add name="Demo_MemberShipProvider"
            type="System.Web.Security.SqlMembershipProvider"
            connectionStringName="cnn"
            enablePasswordRetrieval="false"
            **enablePasswordReset="true"**
            **requiresQuestionAndAnswer="true"**
            applicationName="/"
            requiresUniqueEmail="false"
            passwordFormat="Hashed"
            maxInvalidPasswordAttempts="5"
            **minRequiredPasswordLength="5"**
            **minRequiredNonalphanumericCharacters="0"**
           passwordAttemptWindow="10" passwordStrengthRegularExpression="">
    </providers>
</membership>

Hope it helps!