No matter which variable, it only shows "?"

[hrqmonteiro]

My newsboat config:

auto-reload yes   # fetch new content when starting program
reload-time 10    # fetch new content every 10 minutes
notify-always yes # update tmux counters after every fetch
notify-format "%d %n %f"
notify-program "/home/hrq/.config/tmux/plugins/tmux-newsboat/bin/tmux-newsboat"

My tmux section:

set -g status-right '#{prefix_highlight} #{newsboat_unread_articles}'

And it only shows a question mark, even if i use the new_articles or unread_feeds