You've verified that water is available at the inlet. The owner's manual suggests checking and cleaning the filters (Troubleshooting, page 33). The instructions for doing this are on page 32, linked below. Perhaps the dishwasher loaded up the filters when it didn't have incoming water to flush out the debris at the end of the wash cycle.
If after cleaning everything it still doesn't work, we're back to a burned-out inlet solenoid valve. If you're familiar with electrical equipment, you can disconnect power to the dishwasher, disconnect one or both terminals from the solenoid coil (so other connections in the dishwasher don't interfere with the measurement) and measure the resistance of the coil. If it reads infinite on any range, or more than a million ohms, the electromagnet coil is burned out and the coil or valve assembly will have to be replaced.
Turn off the water to the dishwasher and unplug it. Disconnect the water line to the dishwasher and place it in a bucket. Have somebody turn the water back on until water goes into the bucket (it may spit, then spray hard), then immediately turn the water off. (If there is a shutoff right at the dishwasher, this is a one-person job. If not, you'll have to holler to the person standing by at the main valve.) Reconnect the water line.
This should take care of any vacuum/air lock issues at the inlet; if the dishwasher doesn't see water flow right away, it may be tripping the error signal.
The worst case I can imagine is that the inlet water solenoid valve overheated because it was on for a long time with no water flowing through it. It may be stuck or burned out.
Indesit IDL700 first two green lights flashing and cycle stops with dirty water left in the machine. CAUSE - blocked or jammed drain pump. SOLUTION - First remove all the filters inside the machine, syphon or sponge up all the water in the sump and check for any obstruction over the fine grill at the very bottom. (we had a pistachio shell covering the hole!). If this doesn't cue it you will need to gain access to the pump. First, turn off the power. Gently lift the machine onto it's side (be ready for some water to spill out!). Remove the bottom plate (6 screws) and disconnect the sump float switch. Remove the single screw retaining the pump to the bottom of the machine and rotate to remove. You should be able to see the rotor blades. With your finger check to see if the pump rotates freely. To dismantle the pump, remove the 3 screws and separate the two halves. Our pump was jammed with an apple stalk!. Reassemble and connect any cables. Apparently this is a known problem with these machines and can be prevented by assembling the filter system correctly and pre-rinsing plates etc. before placing in the dishwasher.
Remove bottom panel, you'll see the element connections in the corner of the base. Unplug the connectors and unscrew the 8mm nut securing the earth wire to the element. Pull the 2 rubber insulation cones that cover the terminals, unscrew the retraining nut to the element and remove the "E" shaped spacer from between the terminals. The element will then pop out of the two holding bracket from inside the machine and remove. To replace - just reverse the procedure.
Try cutting the power to the dishwasher (remove the fuse) for about 30 seconds, then when you put the fuse back in, do it quickly and smoothly so you get a clean power-on without a lot of sparking. This may get the dishwasher controller to do a proper hard power-on reset.
If the problem persists, you may have a hardware failure in the controller. The first thing I'd look for is a failing electrolytic capacitor. Sometimes a power on-off cycle finishes them off. Fortunately, the parts are cheap and readily available from online suppliers such as Digi-Key or Mouser. Unfortunately, you have to have electronic component soldering skills to change them. Often, bad capacitors can be visually identified because the top of the capacitor is domed instead of flat, or for smaller units the aluminum casing is partly pushed off of the rubber or plastic base.
Contrast the bad capacitor on the right with the good one next to it on the left.