After installation or upgrade of PPA Billing error like "Problem with the SSL CA cert (path? access rights?)" appears during synchronization of Online Store and in some other places in UI.
Installation or upgrade of PPA Billing may cause update of Network Security Services in your OS. And there is a known issue that all services that use CURL library need to be restarted.
In order to resolve the issue the PPA Billing node should be rebooted.