Cloud 9 IDE Vue.js unable to preview browser on 8080

Environment: Using t3.small with resized EBS to 20GB; Connecting from: Mac OS (Safari or Chrome - current versions)

Repro:

nvm install stable
npm install -g @aws-amplify/cli        # optional (unless testing `amplify run`)
npm install vue
npm install -g @vue/cli

vue create testsite
# use babel, router, lint; vue3

cd testsite
npm run serve

At this point server is running normally with following message:

App running at:

• Local: http://localhost:8080/
• Network: http://xxx.xxx.xxx.xxx:8080/

However Cloud9 reports following error: Cloud9 Help You may be using the wrong PORT & IP for your server application. Try passing port 8080 to properly launch your application.

We can continue installing Amplify to show it also fails with amplify run:

amplify configure     # create or use existing amplify user passing appropriate key/secret ids
amplify init                # use defaults
npm install aws-amplify @aws-amplify/ui-components
amplify add auth      # optional - I was trying to test drive Cognito; some code changes required, but not relevant for this test
amplify push
amplify run

Same result as with npm run serve.

Reviewed following references, but did not find any working solutions:

• https://docs.aws.amazon.com/cloud9/latest/user-guide/app-preview.html#app-preview-run-app
• https://docs.aws.amazon.com/cloud9/latest/user-guide/troubleshooting.html#troubleshooting-app-preview
• https://repost.aws/questions/QUyfyfFI92TO6lN6s6Ti-7Ig/can-no-longer-preview-running-applications-vfs-connection-does-not-exist
  • Note: In Chrome this seems to now be "SameParty cookies to be first-party" and in Safari disabling prevent cross-site tracking and block all cookies - neither worked for me

When I had first started while following the initial Cloud 9 guide I was able to get the preview application to work while using the default t3.micro instance on Safari. After upgrading to t3.small it did not work any longer, though the t3.micro instance was failing in numerous other ways due to low memory, so this was not a viable setup. Following through the Cloud 9 instructions to create new environment instances I was unable to get any working Preview scenarios in any of the environments following various variations on the setup and sequencing of the vue3 and vue/cli installation.

Any additional suggestions are appreciated.