Can you spot that mistake?

Dexter, a math lover, claims that he has proven $e^{2i}=1$ , but applying the Euler's formula $e^{ix}=\cos x + i \sin x$ , $e^{2i}$ is actually a complex number . In which of these steps does he first make a mistake?

Step 1 : As we know, $e^{i\pi}=-1$ .
Step 2 : Squaring both sides, we get $\big(e^{i\pi}\big)^2=1$ .
Step 3 : Exchanging the exponents, $\big(e^{2i}\big)^\pi=1$ .
Step 4 : Multiplying $\frac{1}{\pi}$ at the exponents of both sides, we claim that $e^{2i}=1$ .