A lot depends on the version you are using. Previous comment seems to be pointing to an older version than the present version 12.3 which allows only responsive projects. Breakpoint views were the oldest way to create responsive projects in version 9.

So, please, check the full version number which you find under Help, About Captivate.

Especially for projects meant to be viewed on mobile devices, it is important to  keep the file size as low as possible. Avoid long video and audio clips, reduce their size for an optimal quality/size ratio. Test in multiple browsers (avoid Safari and IE). Hardware and software, as well as bandwidth play a role. The new version is rendering very slowly, did you wait long enough? Did you activate AutoPlay which is available in the new version?

To create mobile-friendly or responsive Captivate projects, keep the following considerations in mind: 

• Utilize responsive design features to establish breakpoints for different device sizes. 

• Resize and reposition objects within each breakpoint to ensure they are properly visible on smaller screens.  

• Additionally, ensure that all media elements, such as images and videos, are optimized for mobile viewing.  

• Use the “Preview” option and select “Device Preview” to test how the project appears on various mobile devices.