שגיאת בנייה של Discourse: אירעה שגיאה בעת התקנת rbtrace (0.5.1), ו-Bundler אינו יכול להמשיך

Debian 9 has been superseded by Debian 10 (“buster”). Security updates have been discontinued as of July 6th, 2020.

You may want to take your backup and migrate to a new server running a current OS version.