From the looks of it, this might be an issue for any WordPress installation ( any web app in general ), regardless if you use eLearnCommerce or not.
Possible issues :
Ajax Requests not working in admin, not reaching the server at all.
Sometimes WordPress Post / Page / Course save not working.
Literally anything that would make an Ajax / XMLHTTPRequest on the same domain.
Steps to fix :
I. Go in your search bar :
II. Type in : chrome://flags/#out-of-blink-cors
You should see something like :
III. Enable the Out of blink CORS option.
IV. After enabling it, you'll notice the Chrome Notification to restart your browser, so that changes that into effect.
V. If you've pressed the Relaunch Now ( based on browser language ), the issue should be fixed.