phpBB : Critical Error

Error creating new session

DEBUG MODE

SQL Error : 1062 Duplicate entry 'a9b1cb5a533526b40b78ed2f476784db' for key 'phpbb_sessions.PRIMARY'

INSERT INTO phpbb_sessions (session_id, session_user_id, session_start, session_time, session_ip, session_page, session_logged_in, session_admin) VALUES ('a9b1cb5a533526b40b78ed2f476784db', -1, 1755416755, 1755416755, 'd849d887', 0, 0, 0)

Line : 187
File : sessions.php