Fix error moodle

FIX ERROR ON MOODLE SITE AS SOON AS POSSIBLE
Detectado un error de codificación, debe ser corregido por un programador: PHP catchable fatal error
Debug info: session_regenerate_id(): Failed to create(read) session ID: files (path: [dataroot]/sessions)
Error code: codingerror
Stack trace:
line 433 of /lib/setuplib.php: coding_exception thrown
line ? of unknownfile: call to default_error_handler()
line 293 of /lib/classes/session/manager.php: call to session_regenerate_id()
line 82 of /lib/classes/session/manager.php: call to core\session\manager::initialise_user_session()
line 785 of /lib/setup.php: call to core\session\manager::start()
line 29 of /config.php: call to require_once()
line 30 of /index.php: call to require_once()