phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '19974f4b1bb6609c68e80a2e595bd5d6' for key 'PRIMARY'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('19974f4b1bb6609c68e80a2e595bd5d6', -1, 1422436345, 1422436345, '365cef78', 15, 0, 0)

Line : 245
File : sessions.php