Problem with noise covariance of simulated signal

I got simulated signal. Added it to matlab and added some of noise awgn(SimSignal.F,10,'measured'). After i import this signal to brainstorm and trying to noise covariance, i get these errors

Error using bst_noisecov
File has no time dimension: Subject01/common/data_221028_1521.mat

Error in tree_set_noisecov (line 71)
bst_noisecov(iTargetStudies, iStudies_data, iData, [], isDataCov);

Error in tree_callbacks>@(h,ev)tree_set_noisecov(bstNodes,'Compute',0) (line 2580)
gui_component('MenuItem', jMenu, [], 'Compute from recordings', IconLoader.ICON_NOISECOV, [], @(h,ev)tree_set_noisecov(bstNodes, 'Compute', 0));

How can i solve this problem?

Can you run the noise covariance computation on the simulated signals with no added noise?
If so, then it is you file modification that is incorrect: if you modify manually the values withing a file in the Brainstorm database, you should not modify the dimensions of any of the variables.

The data structure is documented here:

To learn how to write Brainstorm scripts: