If your project uses any native extensions (ie has native code such as C++, Java or Objective-C) or if your project uses an application manifest (to remove unused systems such as physics) it has to be built online at least once so that our build server can create a custom game engine with your extensions and with unused systems removed. This custom engine will be cached in .internal/cache and used for subsequent builds (which can be done offline).
When do you get the error? When opening the project or when doing Project->Bundle?
I had read that about cacheing the engine, so I made sure to create a bundle first. No luck though.
The error occurs when selecting Project > Bundle. It opens and builds in editor fine.
I just did a test with a new empty project and it successfully created a bundle offline. But if I add a dependency like DefOS, I get the error (after bundling online to cache the engine then going offline to bundle again).
I don’t think DefOS is the culprit, because I also tried this with defold-orthographic and got the same result.