Principal Tensor directions error

Hi !

I'm currently working in a solver for the principal direction of a stress tensor, but while solving the system for the directions a get a fail error. Please if someone can help me with any information it would be great.

Solving manually i got this

My current work is here:

clear all
clc

%Input 

disp('Informe as componentes do tensor ')
T11=input(' Elemento 1;1 ');
T12=input(' Elemento 1;2 ');
T13=input(' Elemento 1;3 ');
T21=input(' Elemento 2;1 ');
T22=input(' Elemento 2;2 ');
T23=input(' Elemento 2;3 ');
T33=input(' Elemento 3;3 ');

%Tensor informado

T=[T11 T12 T13;T21 T22 T23;T13 T23 T33]

%Solução Tensões/Deformações Principais
syms x 
TL=[T11-x T12 T13;T21 T22-x T23;T13 T23 T33-x];
deter=det(TL);
princ=solve(deter,x)

%Solução Direções Principais
%syms N1 N2 N3
%A=[(T11-princ(1)) T12 T13;T21 (T22-princ(1)) T23;T13 T23 (T33-princ(1))];
%B=[0;0;0];
%N=[N1;N2;N3];
%EQ=A*N;
%Dire_1=vpasolve(A*N==B,[N1 N2 N3])

A=[(T11-princ(1)) T12 T13;T21 (T22-princ(1)) T23;T13 T23 (T33-princ(1))];
B=[0;0;0];
Direcao_1=inv(A)*B