That part is hot and wet. So I thought just glue will not work. So I thought glue with a shelf around could work. The shelf takes the pressure and the glue seal the liquid. 

I used ABS with the finest resolution (0,2mm)  my printer makes and a glue which works up to 120 deg. which is flexible and has the capability to fill gaps. The combination I thought should work perfectly.

For drawing  and fixing the coffee maker I required appr. an hour. The glue was slightly more expensive than the spare part - but if the ...... German supplier don't want to deliver to Switzerland what choice you have?