I have the following error in the Chrome Dev Tools console on every page-load of my Node/Express/React application:
Unchecked runtime.lastError: Could not es
I'd been getting the exact same error (except my app has no back-end and React front-end), and I discovered that it wasn't coming from my app, it was actually coming from the "Video Speed Controller" Chrome extension. If you aren't using that extension, try disabling all of your extensions and then turning them back on one-by-one?