Divergence of the Fourier series of the Weierstrass–Mandelbrot cosine function

The set of $M_c$ – the points of divergence of the formal trigonometric Fourier series of the Weierstrass–Mandelbrot cosine function $C(t)$, given on the segment $[-1,1]$ is considered. In particular, it is shown that on the segment $[0,1]$ the Fourier series of the function $C(t)$ diverges in all the points of the subset $M_c(1/2)$, having zero measurement and the cardinality (power) of continuum when the function parameters are: $b=3$ and $D=1,5$.