A. Check the file format and size of the files you are trying to upload. Kilonotes may have limitations on the types of files it can handle. Try converting the file to a supported format (like PDF or JPEG) and ensure it is under the maximum size limit. If the app continues to crash, try clearing the app's cache by going to Settings > Apps > Kilonotes > Storage > Clear Cache.
B. If the issue persists, consider uninstalling and reinstalling the app. This can help reset any corrupted data that may be causing the crashes.