I can only offer things to try:
- Check all of you assets have good naming conventions (avoid whitespace, symbols etc…)
- Make sure ALL of your blueprints / code can compile correctly
- Check the output / cook settings of your project (version, target, etc…)
- Make sure you aren’t referencing / using any deleted assets
- Check what plugins you are using, apparently sometimes they can cause build failures for particular targets
- It’s possible some of your local content has become corrupted; in the launcher you can run a verify content to make sure that the editor content is correct and re-download anything which is incorrect
- Try to check any log files to see if you can get more information on the build failure
Good luck!