.The previtreous dynamics in the glass-forming monomer, glycerol monoacrylate (GMA), was tested using the broadband dielectric spectroscopy (BDS). The measurements revealed a clear dynamic crossover at the temperature T_{B} = 254 K and the time scale tau (T_{B}) = 5.4 ns for the primary (structural) relaxation time and no hallmarks for the crossover for the DC electric conductivity sigma_{DC}. This result was revealed via the derivative-based and distortions-sensitive analysis mathrm{d} ln H_{a}/mathrm{d} (1/T)vs. 1/T , where H_{a} stands for the apparent activation energy. Subsequent tests of the fractional Debye-Stokes-Einsten relation sigma_{DC} (tau_{alpha})^{S} = mbox{const} showed that the crossover is associated with S = 1 (mathrm{for} T > T_{B}) rightarrow S = 0.84 (for T < T_{B}. The crossover coexists with the emergence of the secondary beta relaxation, which smoothly develops deeply into the solid amorphous phase below the glass temperature T_{g}.Graphical abstract