Verify the file path, double-check that the file '/opt/SPECjAppServer2004/output/690/Atomicity.html' exists in the specified location. Ensure that the path is accurate and matches the actual location of the file. Check file permissions, make sure that the application server has the necessary permissions to read the file. The user or process running the application server should have read access to the file and its parent directories. You can use the 'ls' command (e.g., 'ls -l /opt/SPECjAppServer2004/output/690/Atomicity.html') to view and modify the file permissions if needed. Validate file integrity, if the file exists but the error persists, it's possible that the file is corrupted. Try accessing the file from another location or check if you have a backup copy. If available, replace the file with a known working version. Restart the application server, in some cases, restarting the application server can resolve temporary file access issues. Restart the application server and see if the error still occurs. Review application server logs, check the logs of the application server for any additional error messages or clues related to the file reading issue. The logs may provide more specific information about the root cause of the problem.