To package the project, I clicked on: File - Zip Project menu to create the zip file.
The project can be reopened on my PC with no problem, and clicking on the cues will make them play normally.
the cues were created by clicking on Create Multiple Cues, no plugins were involved. However in the .uproject file, there was a plugin enabled by default. Previously the support email told me to disable unused plugins, so I deleted that block and the 2nd upload this check has passed.
Thanks a lot for your reply. Any thoughts on my above steps?
Those all seem correct. I would try saving again after disabling the plugins. If you can, try and see if you can open your project on another PC, otherwise I would send it back in post saving.
If none of that works, you should be able to directly reply to your review via email and ask for more information directly without needing to go through the support ticket process. This still follows the 1-3 business day cycle for updating your review/replying to questions about the review.