Optimization problem with Mosek

I want to solve the following problem: Maximize \sum_{i=1}^{n} \log(v_i) subject to v_i \geq 0 and A' v \leq n 1_m, where A is a n \times m matrix of positive reals, using Mosek in Matlab. This is my code:

n = 10; % Number of variables

m = 20; % Number of constraints

F = rand(n, m)*100; % Example n x m matrix of positive reals

A = F'; % Transpose of F for the constraint matrix

b = n * ones(m, 1); % Right-hand side for constraints

% Optimization problem

prob.c = -ones(n, 1); % Coefficients for the objective function (maximize sum log(v_i))

prob.a = sparse(A); % Constraint matrix A'

prob.blc = -inf(m, 1); % Lower bounds

prob.buc = b; % Upper bounds

% Lower bounds (v >= 0)

prob.blx = zeros(n, 1); % Lower bounds for v

prob.bux = inf(n, 1); % No upper bounds for v

% Exponential cone constraints for log(v_i)

prob.cones.type = 'pexp'; % Type of cone (primal exponential)

prob.cones.sub = (1:n); % Indices of the variables involved in the cone

prob.cones.dim = repmat(3, n, 1); % Each cone has dimensionality 3

% Call MOSEK optimizer to solve the problem

[r, res] = mosekopt('minimize', prob);

I tried a few variants, but so far I always get error 1200. Any help?