scanner on my mfc-l2750dw won't scan to my computer anymore, it just says 'check connection'.

Diagnosis

The "Check Connection" error on the Brother MFC-L2750DW is rarely a mechanical failure of the scanner bed. Instead, it is a communication breakdown between the Brother ControlCenter4 software and the printer's network interface. This typically occurs because the printer's IP address has shifted via DHCP, leaving the computer attempting to send a "wake up" command to an address that no longer exists on your local network. Furthermore, this error is frequently triggered by Windows Update overriding the proprietary Brother TWAIN driver with a generic "Class Driver." While the generic driver allows basic printing, it often lacks the bidirectional communication required for "Scan-to-PC" functions, resulting in a timeout and the "Check Connection" prompt. You can confirm this by attempting to scan using the Brother iPrint&Scan app; if the app works but the physical buttons on the machine do not, the issue is specifically with the ControlCenter4 service or the driver mapping.

How to Fix It

To restore the connection, you must synchronize the network IP and refresh the driver stack. Follow these steps exactly:

1. Print a Network Configuration Report from the printer: Press Settings > All Settings > Print Reports > Network Config. Note the "IP Address" listed (e.g., 192.168.1.15).
2. On your PC, open Control Panel > Devices and Printers. Right-click the MFC-L2750DW and select Printer Properties. Under the Ports tab, ensure the port checked matches the IP address from your report. If it doesn't, click Add Port > Standard TCP/IP Port and enter the current IP.
3. Open the Brother Utilities folder from your Start menu and launch ControlCenter4. Go to Configuration > Scan Settings > Scan to PC. Ensure your computer name is correctly selected in the dropdown menu.
4. Restart the Brother Status Monitor service: Press Win + R, type services.msc, find Brother Help or Brother Status Monitor, right-click it, and select Restart.
5. Perform a test scan directly from the printer's physical panel by selecting Scan > to PC > File.

If That Didn't Work

• Disable Firewall Packet Inspection: Third-party antivirus software (like Norton or McAfee) often flags the Brother scan port (UDP 54925) as a security risk. Go into your firewall settings and create an "Inbound Rule" to allow all traffic for the BrSvr.exe and Okmdvr.exe processes.
• Assign a Static IP: To prevent this from recurring, access the printer's web interface by typing the printer's IP address into a web browser. Navigate to Network > TCP/IP and change the Boot Method from DHCP to Static. This locks the address so the computer never loses the path.
• Full Driver Purge: If the TWAIN driver is corrupted, uninstall all Brother software. Go to C:\Windows\twain and delete the Brother folder. Download the "Full Driver & Software Package" from the official site and reinstall. This forces the OS to overwrite the generic Windows Class Driver with the full-featured Brother driver.
• USB Cable Swap: If you are using a USB connection rather than Wi-Fi, the "Check Connection" error can be caused by a failing USB 2.0 cable or a loose port. Swap the cable for a high-shielded cable (under 6 feet) and move the connection to a rear USB port on the motherboard rather than a front-panel hub.

Heads Up

• Avoid "Add Device" in Windows Settings: Never use the built-in Windows "Add a printer or scanner" tool for this model; it installs a restricted driver. Always use the Brother Full Software Package to ensure scanning functionality.
• Sleep Mode Latency: The MFC-L2750DW can sometimes "deep sleep," causing the first scan attempt to fail. Press the Home button to wake the machine before initiating a scan from the PC.
• Firmware Updates: Periodically run the Brother Firmware Update Tool. Outdated firmware on the L2750DW often causes compatibility issues with newer versions of Windows 10 and 11.