Required (network) permissions for external API on Windows

We are having trouble using the external API. Two people can join a meeting but if one person is sharing something, the shared content is not shown at the recipients screen (even though the “sharing icon” is visible).

This is most likely due to user rights. Internet access permissions are very limited because of corporate networks. We added all URLs that we thought are required but still sharing does not work. Which user rights/URLs do we need to configure so that with external API will work without granting unlimited internet access?