Redmine

How can I remove the redmine URL? The server is debian 9 with apache2.

Environment:
Redmine version 3.4.6.stable
Ruby version 2.3.3-p222 (2016-11-21) [x86_64-linux-gnu]
Rails version 4.2.8
Environment production
Database adapter Mysql2
SCM:
Filesystem
Redmine plugins:
no plugin installed