HTML5 published from Captivate 8 not loading

I have exported HTML5 file from Captivate 8 and Captivate 9.

File exported from captivate 9 is getting loaded in iframe tag. But file exported from captivate 8 not able to load.

Only loader displays on screen.

<div align="center" >

                    <iframe width="940px" height="550px" src="links/intro/index.html" style="display:block; margin:0; padding:0;" frameborder="0" scrolling="no" allowfullscreen ></iframe>

                  </div>