Error: Line search cannot locate an adequate point after MAXLS function and gradient evaluations.

[ChenLiumeng]

When I apply my data to the synthetic control method, the following error occurs:

**At iterate 9 f= 1.88176D+02 |proj g|= 9.95029D-01
ys=-1.176E-04 -gs= 9.593E-02 BFGS update SKIPPED

At iterate 12 f= 1.87726D+02 |proj g|= 9.93929D-01
ys=-4.743E-08 -gs= 2.418E-03 BFGS update SKIPPED

Bad direction in the line search;
refresh the lbfgs memory and restart the iteration.

Bad direction in the line search;
refresh the lbfgs memory and restart the iteration.

Line search cannot locate an adequate point after MAXLS
function and gradient evaluations.
Previous x, f and g restored.
Possible causes: 1 error in function or gradient evaluation;
2 rounding error dominate computation.**

I searched for the cause of the occurrence showing that it could be due to an unreasonable number of iterations, so I made a change to n_optim= in SyntheticControlMethods/main.py as below, but found that the problem persisted.

How should I solve this please, thank you very much!😊
This is the version of each package for the environment I'm using

tests.zip