Imaginary parts of complex X and/or Y arguments ignored

I solved problem in MATLAB and got a good results, but there is:

Imaginary parts of complex X and/or Y arguments ignored

What is the problem and how to solve it.

Part of the code is bellow, where Ta and V are experimental data (T=f(V)), and Cfit is fiitted temperature.

figure(1)
plot(V, T, 'p')
hold on
hlp = plot(Vv, Cfit);
hold off
grid
xlabel('Volumen')
ylabel('Temperatura')
legend(hlp, 'C(V)', 'Location','N')

Thanks in advance!

[madhan ravi]

Duplicate of https://in.mathworks.com/matlabcentral/answers/456896-imaginary-parts-of-complex-x-and-or-y-arguments-ignored