Hello Harsha,
Happy to help! I appreciate the troubleshooting you've already done. I haven't heard of similar reports, and I was able to upload a sample Storyline course to Review.
Have you tried publishing a new Storyline course to Review with only one slide and a shape and see if the internet connection error will appear? If it only happens to specific projects, import the slides of one affected course to a new Storyline file and see if it helps.
Regarding uploading to Review 360 manually, I'd like to confirm the steps you applied to obtain the zipped file. Did you click the Review 360 tab in the Publish window, then select the Publish locally for manual upload option? Please see the article below for details.
I am looking forward to your response.
