If you got an issue when you want to deactivate On-demand link with error message "Failed to update On-demand" then you should refer to this help guide. 

It usually happened because of the "Unique character" inside of the On-demand URL such as  /, !, @, $, #, %, dan ^. 

Therefore, what we can suggest is, to ignore the existing On-demand link that has a unique character on it. 

Then, you can create a new On-demand link, and avoid a unique character on the URL.