Can't save scanned images.

I use a Mac 10.11.6/ Canon i sensys MF8040cn with a wireless connection. The printer and the computer communicate. In the past, I have been able to scan and save the images in different formats, but this has now stopped. I can print and scan using MF Toolbox. However, when the scan is finished I get this message: Saving of scanned images has stopped. Scanned images that have not been saved will be deleted.

Any help appreciated

michaelion