How to run nntool/ regression learner coding in app designer?

Hello, I am new in Matlab, I want to run nntool regression prediction in appdesigner, when i read excel files, it can't run the program. it shows errors.

Below shown are the codes.

X = readtable('Fypinputdata.xlsx','Sheet',2);

app.UITable3.Data = X;

T = readtable('FypTargetdata.xlsx','Sheet',2);

app.UITable3_2.Data = T;

[net,tr] = train(net,X,T);

nntraintool

nntraintool('close')

plotperform(tr)

testX = X(:,tr.testInd);

testT = T(:,tr.testInd);

testY = net(testX);

perf = mse(net,testT,testY)

Y = net(X);

plotregression(T,Y)

e = T - Y;

ploterrhist(e)

attached Below is my error :

Thanking you in advance