Reference to non-existent field 'sol'

1

I am trying to debug my code. After a couple of runs, matlab suddenly gives this error. It is said that “??? Reference to non-existent field ‘sol’.”. I am using Mosek solver now.

Simple problem can be solved. For example

cvx_begin
variable x;
minimize(x.^2);
subject to
x >=0; x<=1;
cvx_end
2

Hello
I got the same error. it does not happen at the beginning but after some iterations of generating random variables. If you have found the cause of this error please let me know.
Thanks