Here are some depictions of electromagnetic wave, similar to the depictions in other places:

![enter image description here](https://idol.union.edu/malekis/Phys%20&%20Pol%202010/Images/e&mWave.gif)
![enter image description here](https://micro.magnet.fsu.edu/primer/java/wavebasics/basicwavesjavafigure1.jpg)
![enter image description here](https://i.stack.imgur.com/3sXXV.gif)

Isn't there an error? It is logical to presume that the electric field should have maximum when magnetic field is at zero and vise versa, so that there is no moment when the both vectors are zero at the same time. Otherwise one comes to a conclusion that the total energy of the system becomes zero, then grows to maximum, then becomes zero again which contradicts the conservation law.