Why iframe is not supporting in solo learn

Answer 1

SoloLearn page was loaded via HTTPS and thus blocking insecure contents (HTTP) by default.

I'm not aware of any other methods besides embedding a HTTPS page in the iFrame. Here's an example:-

https://code.sololearn.com/Wb819DHXTLW6/?ref=app

Answer 2

Check out this:
https://code.sololearn.com/WtV7rvY8TJyl/?ref=app