If you've removed the trainer, removed our launcher, ran integrity check, then the trainer has nothing to do with your problem, especially if you reinstalled the game.
Thanks for replies, and yes, I agree with you, the trainer does not seem to be the direct cause of this problem. After some research, I noticed such error message often comes with easyAntiCheat. However, in my situation, this error did not appear before I use the trainer.
At the first time I use this latest trainer program, it asked me to install .net core 2.2
I think the issue might come from this. It might well be some files changed during the installation of .net core; such as "hid.dll". So my guess is, reverting this file or all files modified back to original state, the problem can well be solved.
If this problem happens in such combination, other games using easyAntiCheat may come with similar issues in the future.
I can't wait to get back online while not using trainer... But, thanks for any help come in the way.
Have you tested this yet? If so has anything happened to your account?
Though I still cannot fix the error message issue, I found an alternative way to get through it. I can play Jump Force online with my NVIDIA Shield TV via NVIDA NOW service, which runs my account and my game from Nvidia server. Because I am in Asia, and no Nvidia Server in Asia, the connection is poor, images are blurr, but latency is still acceptable.