The most common reason behind the "brother printer in error state" issue is a poor internet connection. Restart your printer, computer, and router to fix the issue. You can simply unplug the power cord from the electrical outlet, and then plug it back in to restart the devices. Also, update the printer drivers to the latest version. Corrupted or outdated printer drivers and software can also cause your device to go offline. So, visit the Brother printer's official website and download the latest version of the software for your device. If nothing helps you to fix the issue, run the printer troubleshooter to bring the device back online.