Newbie would like his DIY Arduino schematic checked

Projects General Guidance
6

I think you have got the crystal connected wrongly.

Here is the pin-out from the datasheet:
Crystal Pinout.png

Pins 1 and 3 are the 'active ' pins of the crystal, and should be connected to the pins of the microcontroller and the capacitors, as you have done.

However pins 2 and 4 are both connected to the metal case of the crystal. They should be connected to the circuit GND.

By connecting pins 2 and 4 the way you have, you have used the case to short circuit the two active crystal pins together.