dpc-web/app/views/devise/mailer/unlock_instructions.html.erb
<h1>Hello <%= @user.first_name %> <%= @user.last_name %>!</h1>
<p>Your account has been locked due to an excessive number of unsuccessful sign in attempts.</p>
<p>Click the link below to unlock your account:</p>
<p><%= link_to 'Unlock my account', unlock_url(@resource, unlock_token: @token) %></p>