Nowadays an Ad Server can call another one and so one, due to programmatic. So you might have one Ad server enforcing and serving their tags in HTTPS, but in th

Nowadays an Ad Server can call another one and so one, due to programmatic. So you might have one Ad server enforcing and serving their tags in HTTPS, but in the end the little local Ad Server which is part of a bigger network doesn't have the HTTPS and so his material isn't delivered.