Retriving FILING (e.g. 10-K files) with the API: Could we have a problem of permissions?

We’re interested in downloading the Annual Reports filings (e.g. 10-K files) with an API
solution in order to not to do it manually, the code we followed doesn’t return any
data.
We’ve seen that somebody has already had the same issue following the same code
and it seems to be a licensing matter. We don’t know if that’s our case.
The code that we use is the same as it appears here:
https://developers.lseg.com/en/article-catalog/article/introduction-to-filings---python
When we use the requestSearch function we define it returns a 404 error (as it cannot
find the files).

Could it be a problem of permission?