QuickBooks Error 6123, 0 typically occurs when there are issues with your company file or network connectivity. This error may prevent you from opening or working with your company file, and can be triggered by various factors such as damaged file components or network problems. To resolve this issue, you can try troubleshooting steps like checking your network connection, updating QuickBooks, or restoring a backup. For immediate assistance, dial 1–855–738–2784 for expert support.