No variable result of cvx

My cvx code is

and there is error :
Error using cellfun
Non-scalar in Uniform output, at index 10, output 1.
Set ‘UniformOutput’ to false.
Error in cvx_pop (line 29)
s2 = cellfun( @cvx_id, s2 );

Error in cvx_end (line 15)
evalin( ‘caller’, ‘cvx_pop’ );

how to deal with it?