Bad score when training "KukaBulletEnv-v0"

[HaoyuanXu]

I have been training bullet_kuka_grasping for a long time.
Using 'python train.py bullet_kuka_grasping -e 16 -n 16 -t 16' ,nearly training a week.

but the best score was likely to converge to -1776.
How can I solve this problem? Thanks in advance!