Hi All, I decided to use YAML session and added following codes to config.yml reading article of which link is below: https://metacpan.org/pod/Dancer2::Manual#SESSIONS 1 session: YAML 2 engines: 3 session: 4 YAML: 5 session_dir: /tmp/dancer-sessions It works but at my .pm file, following definition is underlined use Dancer2; and when I mouse over above definition I see following warning : YAML Warning: Duplicate map key found. Ignoring ..... I also attached full warning message screenshot I removed 1st line above but it warning still exists. -- Kadir Beyazlı GSM : +90 535 821 50 00