My first post so feel free to ignore me.
Something that hasn't been mentioned so far is the temperature.
Leave it a while to heat up (the portafilter should be hot to the touch before you do anything else, you can run boiler water through it to get it to this point more quickly).
Also I don't know how much Delonghi machines have changed in the past 8 years but mine has a very large dead zone in the thermostat. I find running the pump for ~ 10 seconds till the light goes out (saying the boiler isn't at temperature) then locking in the filter and starting the pump as soon as the l