The F1 error on a Brother embroidery machine usually indicates a problem with the machine’s needle position sensor. Here are some steps you can take to fix the issue:

1. Turn off the machine. Turn off the machine and unplug it from the power source.
2. Check the needle. Check the needle to make sure it is properly inserted and not bent or broken. Replace the needle if necessary.
3. Check the needle position sensor. The needle position sensor is located near the needle. Make sure it is clean and free from any dust or debris. Gently wipe it with a clean, dry cloth.
4. Check the sensor lever. Check the sensor lever to make sure it is not blocked or jammed.
5. Restart the machine. Once you have checked these components, plug the machine back in and turn it on again to see if the F1 error has been resolved.

If these steps do not solve the F1 error, it may indicate a more serious problem with the machine’s internal components. In this case, it is best to contact a qualified technician or the manufacturer for assistance.