Hi! I also used to encounter an error every time I tried to submit files. Not sure if it’s the same error though. Nonetheless, I managed to solve my issue by contacting Perforce. They have one of the BEST technical supports I’ve ever seen! (and I wasn’t even a customer yet) They replied my mails back almost instantly and they even offered to make a quick zoom meeting to solve my issues. (I just wanted to mention how nice they were, so please don’t request that yourself, assuming you’re entitled to it) To save time, you can explain to them that you saw reports online stating that some people have issues on submitting due to a trigger, and requires a Python file named “CheckListTrigger” being removed from your remote computer to resolve the issue. At least that was the root problem of my issue. But they said that it’s not about something I did, and it’s a system problem. So that might be what’s going on in your case as well. Hope this helps 
Btw I just remembered that error message you sent wasn’t the same with what I encountered. I would say check users but that doesn’t make any sense because… how can you even launch P4V if your username / password is invalid 
Anyways so it’s probably a different issue than what I faced but still, I think you’ll be able to solve it by contacting Perforce