RO/DI Died

[hillegom]

So how long have you been running this unit with the same filters?

As Marko said, try running water through without the filters. However, disconnect the RO membrane. You do not want to run chlorine water through it. Test all the hoses to look for an obstruction.
If everything is ok, then put the filters back in and connect up the RO membrane backwards to flush it. Don't switch the ro water with the waste water, just switch the ro in to ro out, your good water. Then flush for 2-3 min.

If you have been running the filters, the particle and the carbon for over a year, I would switch them for new ones.