When you do a Preview publish to HTML5 Captivate tries to create a temporary web server environment in which to run your project output. That web environment is the html5temp14232374726875pre part of the error message. The web browser is trying to resolve the web address to a specific IP address and is running into problems because it cannot find a web domain with that specific name. That's why it throws ERR_NAME_NOT_RESOLVED.
There are several reasons why this can happen but whenever it happens to me I am generally able to resolve it by just going into my Windows settings and changing the Default Application for HTML pages to a different browser. If the current default browser is Microsoft Edge, I change it to Chrome, or vice versa. I do not know WHY this fixes the issue, but it does. The issue may later reappear and then you just change the default browser back again to reset things.
It would be lovely if someone inside the Adobe Captivate team were able to comment on this issue (it's very common) and explain why it happens, but they don't generally offer any help here on the forum. We very much WANT them to.
Thanks for the assistance, RodWard. I tried changing the Default Application for HTML pages to Chrome and Firefox but unfortunately, getting the same error. Currently, I just have the slides in my project. I have the first slide as the beginning slide and trying to preview by selecting 'from this slide' option. Still at a loss.
Sounds like you need to contact Adobe Support and get them involved. This is just a user form, not Adobe Support.