phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry '628d2f69788556de849d9cf5d115388c' 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 ('628d2f69788556de849d9cf5d115388c', -1, 1472653338, 1472653338, '17144d64', -1000, 0, 0)

Line : 187
File : sessions.php