Illegal operation: {log-affine} - {log-affine}

My purpose is to use norm to describe Euclidean distance,but it does not work ,the code is
for m = 2: M
norm((Q(:,m) - Q(:,m-1))) <= DMax;
which Q is 2*M matrix,which stored some two-dimensional coordinates,there have a constraint as follow,I try to use norm to describe it but cvx reject it with error :Illegal operation: {log-affine} - {log-affine},

how can I solve it?thank you sir!

Don’t use gp mode. If you use gp mode, you have to follow its rules, which are different than non-gp DCP rules.