It's possible that sometimes when you embed an external application or web page in Genially you aren't able to view it.
What have you done wrong? Nothing. It's due to online security protocols.
When you copy the HTML code that an application or web page gives you, which looks something like this:
and you insert it in Genially, it can't be seen, in the Editor or the Preview.
What's happening is that, due to internet secruity protocols, Genially does not accept URLs that being with http. They need to begin with https.
With this small trick, it's possible that the problem is solved. If it's not, it could be that the protocols we mentioned previously have to be reviewed or that their settings don't allow the link to work.