Undefined index: combine_loaded_css_for_admin_only Home › Forums › Newsletter Plugin Support › Undefined index: combine_loaded_css_for_admin_only This topic has 0 replies, 1 voice, and was last updated 4 years, 2 months ago by marcintauter. Viewing 1 post (of 1 total) Author Posts July 20, 2020 at 1:40 pm #256051 marcintauterParticipant Any attempt to send a test newsletter or test email to an email address with my domain suffix results in the error: Undefined index: combine_loaded_css_for_admin_only Please advise… Author Posts Check out our premium plans with priority support. Viewing 1 post (of 1 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In