gaussian fit to the data

I have my data like

x = 1:1934;
y = (Attached below); 

To fit a gaussian distribution, I used

    figure; plot(x,y);  
    myfittype = fittype('B.*exp(-(x-mu).^2/(2*sigma^2))',...
        'dependent',{'y'},'independent',{'x'},'coefficients',...
        {'B','mu','sigma'}); % 
    [myfit2, goodness2, output2] = fit(x,y,myfittype);
    hold on;
    plot(myfit2,x,y);

Even though it fits very incorrectly, I can see a Warning: Start point not provided, choosing random start point.

Ideally, alongwith mu and sigma, coefficent B should also be generated automatically while running fittype. However, it does not.

Any suggestions to improve it?

[Torsten]

I think you mix up "maximum likelihood estimates" and "curve fitting".

Take a look at

https://de.mathworks.com/help/stats/mle.html