Now I am getting worried.

I am not sure but I think the PH6 does not have a pressure gauge?

If it does not and you have connected the rifle to your air tank and opened the air tank valve fully (260bar on the tank guage) then the rifle may well be charged to 260 bar. This is far too high for a PH6 and will lead to the exhaust valve sticking such that no air is shot out when the trigger is fired.
But: When the tank guage said 260 bar, did you then close the tank valve so that no more air could come out?
Did you then open the bleed valve on the line connecting the tank to the rifle? There should have been a rapid (less than or about a second) but short hiss as the line loses air.
If the hiss continues for a longer time, a few seconds and decreases in sound volume, then it is likely that the inlet valve on the rifle is faulty and all the air in the rifle cylinder is coming out.
Make sure valve on tank is shut. When all air is out of the line, disconnect line from rifle. Will it fire (not loaded)? If it is clearly empty then this confirms a rifle valve issue. If it fires but with a much quieter phut then it is likely there is air in the rifle cylinder at too high a pressure. Keep dry firing to expel more air .. the amount of air being shot out should increase as the air pressure in the cylinder goes down. If the rifle was indeed charged to 260 bar (your tank pressure) then it may take over 60-80 firings to reduce the pressure to a pressure that begins to be normal.

Cheers, Phil