If you're using a restrictive firewall or proxy you might want to white-list (allow) these addresses, so Avocode can properly connect.
List of connected domains
manager.avocode.com
cdn.manager.avocode.com
media.avocode.com
designs.avocode.com
designs.app.avocode.com
cloudfront.designs.avocode.com
preview.avocode.com
s3-preview-cdn.avocode.com
gs-preview-cdn.avocode.com
preview-cdn.avocode.com