Changes were announced over 4 months ago, along with info on how to comply with these new changes.
If using a parent param is still not working for you, then you’ve either entered it erroneously (eg, you’ve included things other than the domain portion, such as protocol, port, or path, which should not be included), not included every parent (if you’re using a site-builder such as wix then they will put your content inside another iframe, ALL parents must be included so you need to include every iframe your embed is within as parents), or you’re not serving your page over HTTPS which is a requirement now (with the exception being localhost or 127.0.0.0/8 parents where HTTPS is not required).
I don’t see an embed on the page you linked, so I can’t help you.