On fixing the issue with ytick alignment in groupplot

I am experiencing some issues while trying to have a common y axis scale as well as ticks. I tried some solutions like every plot/.style to ensure the range of the axes over the groupplot is the same but the position of the ticks seem to vary for each plot thereby leading to some misinterpretation of data. Besides, the tick marks on both x and y axes are interfering with the curves in the plot. Could you please help me fix this issue with the ticks? Here is the code.

  begin{tikzpicture}[every mark/.append style={mark size=.7pt}]
    begin{groupplot}[scale=0.36, group style={
       group name=relcost, group size = 3 by 1, horizontal sep=1cm, %group size=3 by 4
       xlabels at=edge bottom, ylabels at=edge left, yticklabels at=edge left, every plot/.style={
                                        ymin=0,
                                        ymax=750000,
                                        enlargelimits=true
                                 }},
       xmin=0,xmax=15,
       %ymin=0,
       ymode = log,
       %log ticks with fixed point,
       %scaled y ticks=real:1e3,
       %ytick={1, 1e+3},
       xlabel={Capacity factor},
       %ytick={0, 10, 100},
       %xticklabels=$pgfmathprintnumber{tick}$,
       %yticklabel=$pgfmathprintnumber{tick}$,
       y post scale=0.36,
       ylabel={System costs},legend columns=-1,
       legend style={font=small},
       % x tick scale label style={
    %at={(0.95,0)},yshift=-1.5em,anchor=north,inner sep=0pt
 % },
  %y tick scale label style={
   % at={(-0.05,0.99)},anchor=east,inner sep=0pt,
 % },
  %scale ticks above exponent={2},
  %scaled y ticks=false
  ]
    nextgroupplot[title=textsc{C-RAN}, legend to name=unnamed]

        % Low-load scenarios
    addplot+ [black, mark=square, mark options={scale=.3, fill=grenadier!30}] coordinates {
            (0.0, 750007.1040631207)
            (3.0, 120007.1040631207)
            (6.0, 20007.104063120714)
            (9.0, 7.104063120713099)
            (12.0, 7.104063120713099)
            (15.0, 7.104063120713099)
    };
    addplot+ [cyan, mark=square, mark options={scale=.3, fill=saffron!30}] coordinates {
            (0.0, 750173.6040631207)
            (3.0, 120173.6040631207)
            (6.0, 20173.604063120714)
            (9.0, 173.6040631207131)
            (12.0, 173.6040631207131)
            (15.0, 173.6040631207131)
    };  
    % High load
    addplot+ [magenta, mark=square, mark options={scale=.3, fill=grenadier!30}] coordinates {  
            (0.0, 750340.1040631207)
            (3.0, 120340.1040631207)
            (6.0, 20340.104063120714)
            (9.0, 340.10406312071314)
            (12.0, 340.10406312071314)
            (15.0, 340.10406312071314)
        };  
    
%   addplot+ [thin, saffron, mark=square, mark options={scale=.3, fill=saffron!30}] coordinates {  
%            (0, 3.8633)
%            (10, 3.6740000000000004)
%            (20, 3.6188)
%            (30, 3.5742999999999996)
%            (40, 3.5340999999999996)
%            (50, 3.4966)
%       };
    nextgroupplot[title=textsc{D-RAN}, legend to name=unnamed]
        
                % Low-load scenarios
    addplot+ [black, mark=square, mark options={scale=.3, fill=grenadier!30}] coordinates {
            (0.0, 723699.4500521545)
            (3.0, 3699.4500521545033)
            (6.0, 3699.4500521545033)
            (9.0, 3699.4500521545033)
            (12.0, 3699.4500521545033)
            (15.0, 3699.4500521545033)
    };
    addplot+ [cyan, mark=square, mark options={scale=.3, fill=saffron!30}] coordinates {
            (0.0, 723745.9702908196)
            (3.0, 3745.3708261968736)
            (6.0, 3745.3708261968736)
            (9.0, 3745.3708261968736)
            (12.0, 3745.3708261968736)
            (15.0, 3745.3708261968736)
    };  
    % High load
    addplot+ [magenta, mark=square, mark options={scale=.3, fill=grenadier!30}] coordinates {  
            (0.0, 723792.4905294848)
            (3.0, 3791.291600239243)
            (6.0, 3791.291600239243)
            (9.0, 3791.291600239243)
            (12.0, 3791.291600239243)
            (15.0, 3791.291600239243)
        };  
    
%   addplot+ [thin, saffron, mark=square, mark options={scale=.3, fill=saffron!30}] coordinates {  
%             (0, 1.5581)
%            (10, 1.4588999999999999)
%            (20, 1.4384)
%            (30, 1.4215)
%            (40, 1.4069)
%            (50, 1.3936)
%       };
        nextgroupplot[title=textsc{f-RAN}, legend to name=unnamed]
    
    % High load
    addplot+ [black, mark=square, mark options={scale=.3, fill=grenadier!30}] coordinates {    
            (0.0, 720009.7601891027)
            (3.0, 27.482156029028516)
            (6.0, 8.98111126865991)
            (9.0, 7.092207390984598)
            (12.0, 7.092207390984598)
            (15.0, 7.092207390984598)
        };  addlegendentry{Cost factor (0)}
    
    addplot+ [cyan, mark=square, mark options={scale=.3, fill=saffron!30}] coordinates {   
            (0.0, 720135.5307859082)
            (3.0, 143.61324740819705)
            (6.0, 135.5307859083099)
            (9.0, 135.5307859083099)
            (12.0, 135.5307859083099)
            (15.0, 135.5307859083099)
        }; addlegendentry{Cost factor (0.6)}
        
        
        % Low-load
    addplot+ [magenta, mark=square, mark options={scale=.3, fill=grenadier!30}] coordinates {
            (0.0, 720227.3887317348)
            (3.0, 232.75047401100414)
            (6.0, 227.38873173479826)
            (9.0, 227.38873173479826)
            (12.0, 227.38873173479826)
            (15.0, 227.38873173479826)
    }; addlegendentry{Cost factor (1.2)}
%   addplot+ [thin, dashed, saffron, mark=square, mark options={scale=.3, fill=saffron!30}] coordinates {
%            (0, 0.5511)
%            (10, 0.41609999999999997)
%            (20, 0.3845)
%            (30, 0.3554)
%            (40, 0.333)
%            (50, 0.3139)
%   };  
    
    end{groupplot}
    node at (relcost c2r1.south) [inner sep=0pt, anchor=north, yshift=-7ex] {ref{unnamed}};
    end{tikzpicture}