Need help in plotting a graph calculated with ``NIntegrate``

Question

This is my Mathematica code,

Get["EDCRGTCcode.m", Path -> {NotebookDirectory[]}]
n = 5;
coord = {t, y1, y2, y3, z};
met = DiagonalMatrix[(L^2 Exp[2 A[z]])/
    z^2 {-g[z, B], 1, Exp[B^2 z^2], Exp[B^2 z^2] , 1/g[z, B]}];
RGtensors[met, coord]
A[z_] = -a z^2;
g[z_, B_] = 
  1 - Integrate[z^3 Exp[-B^2 z^2 - 3 A[z]], {z, 0, z}]/
   Integrate[z^3 Exp[-B^2 z^2 - 3 A[z]], {z, 0, zh}];
csq = (-(-gdd[[1, 1]]) gdd[[3, 3]] gdd[[4, 4]]) /. z -> zs;
 L = 1; a = 0.15; zh = 1;
t[z1_?NumericQ, z2_?NumericQ, B_, pm_] := 
 pm NIntegrate[
   Sqrt[ (csq gdd[[5, 5]])/(
    gdd[[1, 1]] (gdd[[3, 3]] gdd[[4, 4]] gdd[[1, 1]] - csq))], {z, z2,
     zh, z1}, Method -> "LocalAdaptive", Exclusions -> {z - zh == 0}]
plot = Quiet@
   ParametricPlot[{{z1, Re[t[z1, 0.2, 0.2, 1]]}, {z1, 
      Re[t[z1, 0.2, 0.2, -1]]}}, {z1, 1, 2}, 
    PlotStyle -> {Blue, Blue}, PlotRange -> {{0, 2}, {-2, 2}}, 
    AspectRatio -> 1/2];
Show[plot]

The plot is coming up like this.

Though it explicitly depends on $z_2$ and $B$, there is no change in the plot behaviour as I'm changing the $z_2$ and $B$ values.

This is the output for $z_2=0.2$ and $B=0.2$,

In[12]:= Table[{{z1, Re[t[z1, 0.2, 0.2, 1]]}, {z1, 
   Re[t[z1, 0.2, 0.2, -1]]}}, {z1, 1, 2, 1/4}]

Out[12]= {{{1, 0.}, {1, 0.}}, {{5/4, 0.}, {5/4, 0.}}, {{3/2, 0.}, {3/
   2, 0.}}, {{7/4, 0.}, {7/4, 0.}}, {{2, 0.}, {2, 0.}}}

This is the output for $z_2=1.5$ and $B=0.1$,

In[13]:= Table[{{z1, Re[t[z1, 1.5, 0.1, 1]]}, {z1, 
   Re[t[z1, 1.5, 0.1, -1]]}}, {z1, 1, 2, 1/4}]

Out[13]= {{{1, 0.}, {1, 0.}}, {{5/4, 0.}, {5/4, 0.}}, {{3/2, 0.}, {3/
   2, 0.}}, {{7/4, 0.}, {7/4, 0.}}, {{2, 0.}, {2, 0.}}}

Don't know why; all the values are coming 0.

Could anybody help me find where I'm making a mistake, or is there any error in the code?