This repo is stale, no active work happening here now. I actively maintain a fork of the project, but it lives, and it is managed through a different repo — https://github.com/birdofpreyru/react-native-fs.
Such issue ticket is not actionable — it is not enough info to understand / reproduce the issue. Though, I guess, it is either your Excel file is too large to read through RN bridge with the current library implementation, or it might be that your post-processing of the promise is the issue.
In either case, it is unlikely somebody will act on the issue for free :)
}).catch((err) => {