I want to backflush my espresso machine but water still comes out just like I am using a normal filter and not the blind one. What can be the problem?
This can happen if the gasket around the group head is damaged or worn out. Damage can occur if you overtighten the portafilter when locking it in place to brew, and wear occurs just by using the machine normally. Under normal use (once daily at least five days a week), a group head gasket will need to be replaced about every six months.