Thank you for your valuable information. This is all a bit beyond me! Here is a photo of these valves. I guess...

Another photo from a video « Whole Latte Love ».

OK, so, on the far right, almost cut off in the upper photo (Quite well displayed and more central in the lower) is the stepper valve in question, Brass base, white on top, metal and black on the cylindrical part. If the little rod poking out the top moves, then the stepper valve is trying to "flow control" to keep the pressure correct for the programmed profile... It will probably move a little (if it's working) when first turned on as it checks its position.

Obviously no flow/pressure is getting through to the gauge (connected at the top of the brass piece, you can see the pipette leading away from the elbow), because the gauge doesn't move.

Were I working on it, I would open a connection before the stepper to see if flow gets that far, then close it and open one upstream or downstream depending on whether it had flow or not to determine where the blockage or faulty component is. That 90 degree bend copper tube directly after the stepper would be a good first check. We can be almost certain it isn't getting flow because there's really no possible restriction between it and the gauge. Then once proven it gets no flow from the stepper, you're halfway to getting the stepper out to check it for blockage. My current assumption is that there's a blockage in that valve (either it's jammed closed and not moving or blocked with a bit of calcium).

Lastly, maybe you should take it to someone who fixes these things professionally.

Thanks again...
It's a bad quality of photo..., in reality we can see very well the striping and the movement of the valve. I'm just waiting for my machine to start having trouble again to fully open it and take pictures.
In the meantime, one from the back.
It's a bit too complicated for me. Yes I will bring it to the Rocket representative, but not sure if he is familiar with the R60...

Okay, valve movement means it's electronically working, but just clogged somewhere before the block to which the gauge's pipette is connected.

If you carefully open the compression fittings mentioned above (90 degree copper tube off first, then the one on the other side of the stepper), then take the elbows out of the valve base, you can look into both ends of the stepper and see if the clog is visible. The compression fittings can be opened and resealed several times so long as you don't tighten the heck out of them. One hex face past snug (one sixth of a full rotation), is plenty. Overtightening will just mash the fitting. A little teflon on the elbows will help them seal up at the angle they need for reinstallation.

If the trouble is obviously a calcium clog, check your softener, possibly change it or lower its bypass (I don't know what water treatment you have). Good luck.

I'm still waiting for this pressure / flow problem to repeat itself to inspect this famous stepper valve...

Just because I'm curious, if you still read these forums, did it ever recur?
Did you find the issue?

Miracle, the problem is solved by itself!!
It works perfectly well.
I suspect the stepper valve to be the culprit for a moment...