Order of electron filling is

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ .......

It should be 1s² 2s² 2p¹
In this case $2\text{p}$ started filling before 2s, violating aufbau’s principle.
In $2{\text{p}}_{\text{x}}$ two electrons have parallel spin. This violates pauli’s exclusion principle.