Are you using RO water with nothing else added? Like, 0 TDS? As far as I know, see e.g. here, pure RO or distilled water doesn't have enough mineral content to properly extract coffee. I've been using some of the recipes here. Don't know how likely it is as an error, but didn't see anyone else mention.

Yes! as the dose gets smaller, and the grind finer, the shot becomes more boring (the higher extraction means more buffering compounds). If the coffee you are using is really terrible, boring may be the best possible shot. But you can try going with a slightly higher and more coarsely ground dose, say 17 grams, and see what happens. Maybe that shot, with a little sugar, will work best. The idea is to get used to making these dose adjustments as a matter of course.

@Another_Jim
Thanks your answers Jim!.

I will try to up-dose a little as you recommend, and come back with results
The markings inside my basket seem to match to a 16.5 or 17grams after tamping, depending on grind size.
Could i substitute Sugar with Steamed Milk to make the shot work best?, i tend to avoid sugar even if its tastier, because of health.

Are you using RO water with nothing else added? Like, 0 TDS? As far as I know, see e.g. here, pure RO or distilled water doesn't have enough mineral content to properly extract coffee. I've been using some of the recipes here. Don't know how likely it is as an error, but didn't see anyone else mention.]

@inexorable_end

Yes i'm currently using water from a 5 stage RO system which has a "Remineralizing stage" but that stage is worthless, as you can taste water acidity and it "almost" taste like destilled water. I say almost because its Not that bad as destilled by not as good as spring water.
Thank you very much for your detail. i will pay attention to that too. I thought i could access some FIVE SENSES 70/30 WATER, i mean i can make it myself with Baking soda and Magnesium sulphate. Would that be sufficient?



PS:
i uploaded some pictures here , just in case anyone may wonder how my beans, or basket look like:


these are my current beans. if anyone with some serious experience can tell the quality of some beans by sight it would be great. Sorry if the photo is not the best quality.


This is the standard 57mm basked that comes with the machine.


There's a marked line inside may match to a dose of between 16,5 and 17,5 depending on how finely grounded espresso is.

Regards!