"Connection timed out" in BTP Subaccount CF app to a public HTTP endpoint

[szymon_bolek]

Hi gurus!
In my BTP Subaccount, I deployed an app cloned from GIT, but the HTTP endpoint, that is executed within the app gets an error: Connection timed out

In BAS:
I git clone https://github.com/SAP-samples/localization-toolkit-s4hana-cloud-bank-account-validation.git

In manifest_bas.yml chaned <app_name> to plvatpayerslist
In install.sh changed url to proper cf api endpoint from my subaccount.

I executed sh install.sh without problems. Chosen the target subaccount. Application got deployed without problems. 
I did this for many customers already.
Whithin this application, there is a code, that downloads a ZIP file from the internet. In one of the subaccounts, this download gets: Connection timed out

Any ideas I shall check? Where can I troubleshoot this in BTP/Subaccount/BAS?
What might be the problem, that in one client's subaccount it runs and in another it does not.

thank you & kind regards | Simon