Try a fresh install. Delete the steam folder and reinstall the game. And maybe delete the user folder however I don’t think it’s necessary
Safe mode is basically how the game was before you changed anything. So no mods and default settings for everything.
Maybe, delete all the cache files from the document folders, remove all the mods, and clear all the saved stuff, basically separate the mods and just delete the beamng folder and run the game again, you might have to set everything up again, but if it still gives you the issue, better to just reinstall the game. Because if it runs properly on safe mode, then it's probably one of the mods messing with the game files or the cache files.. Do This: Go to documents and remove all mods and keep it in another folder on desktop. Delete the entire beamng folder in the documents. Re open beamng, this might take a while as it is basically resetting the game completely. Then set everything up again (since you cleared all the saved stuff). Run the game in normal mode. So at the moment everything is bone stock with no mods and a completely new beamng documents folder. Then, at your own risk, try out each mod and see if it conflicts with the game or if you see any instability. If the game still gives you the error, when you cleared everything, it's probably the game files that have been screwed. Re install is a must. But if it runs without any issues, it's defo a mod problem. Then find out which mod.
I contacted with devs and Clean Install was help. Now it's all working. Thank you all for yours help.
I had a similar problem. If you are running game on low settings try putting it to normal. That fixed issue to me maybe it will help you too.