Error 200 when saving page in Oxygen

[Qbaska]

Im getting constantly 200 Error when i try to save a page. I dont know what to do :( I dont really even know where to start. Im not a programmer, my coding skills are extremely poor.

Problem started today after some random saving error. When i tried refresh the Oxygen builder, and then save again i was presented with 200 Error.

I will only add also that i tried to disable all plugins (absolutely all), and keep only oxygen on, unfortunately this didnt help. Clearing browser cache also does not help.

All help will be greatly appreciated. I really dont know how to fix this issue and i have deadlines on my head :(