Minimizing a quadratic form: Failed to converge to the requested accuracy or precision within 100 \ iterations

I’m trying to minimize this type of quadratic form:

expr = (-0.1 x1 + x2 + 1.2 x3 + x4 - x5)^2 + (x1 + 1.2 x2 + x3 - x4 -      0.1 x5)^2 + (1.2 x1 + x2 - x3 - 0.1 x4 + x5)^2 + (-x1 - 0.1 x2 +      x3 + 1.2 x4 + x5)^2 + (x1 - x2 - 0.1 x3 + x4 + 1.2 x5)^2 

where x1,…,x5 are integers not simulteneously zero. Then I performed

Minimize[expr,   x1^2 + x2^2 + x3^2 + x4^2 + x5^2 != 0, {x1, x2, x3, x4,    x5}, Integers] 

which apparently yields a solution {4.45, {x1 -> 0, x2 -> 0, x3 -> 0, x4 -> -1, x5 -> 0}}, but with the warning ‘NMinimize::cvmit: Failed to converge to the requested accuracy or precision within 100 iterations.’

Does this mean that the solution is not actually a solution? What is the meaning behind the warning? I can only find information related to ‘NMinimize’ (in which I believe ‘Minimize’ is based).