Hi rhorty,
Please delete and add the printer to the queue.
Please open [System Preferences] > [Printers & Scanners]. Next, click the [-] sign under the printer list to delete the printer. Once the printer has been removed, please follow the instructions below to add the printer back to the window:
1. Click the [+] icon.
If another dialog box does not appear, click [Add Other Printer or Scanner] or [Add Printer or Scanner] after clicking the [+] icon.
2. Register the printer and fax.
2-B. TCP/IP Connection.
2-B-1. Click [IP], and select a print protocol from [Protocol].
If you want to use the machine in an IPv6 environment, select LPD or Socket for [Protocol].
2-B-2. Enter the IP address of the machine to [Address], and select either one of the following options from [Print Using] or [Use]: [Select Printer Software], or [Select Software].
2-B-3. Select a driver that is capable for this machine from the driver list, and click [OK].
2-B-4. Click [Add].
3. Check that this machine is added to the [Print & Fax], [Print & Scan], or [Printers & Scanners] dialog box.
4. Close the dialog box.
Did you download and install "ScanGear V2.5.0 for Mac OS X 10.5/10.6/10.7/10.8/10.9/10.10/10.11" from Canon's website?
Try opening application, select the Canon MF utility folder and choose to open MFtoolbox,an error will appear don't let it discourage you. At the top left hand corner of your screen, next to the apple icon you'll see MFtoolbox, click on it and select network scanner setting from the drop down menu, click on the plus sign and select the MF249dw from the listing, then add. At the top of the screen, to the right of MFtoolbox click scanner and select the MF249dw from the drop down menu. You should be able to scan via the use of rectangle bar that appears with the email, save, pdf, etc.
If the issue continues please contact Canon's support group using the following link: