I would like to suggest that Sonos create a utility that can be run from web/app/etc that checks the ports and URLs of the services it provides for connectivity. It appears that many of the issues I have experienced (and maybe others?) are due to connectivity to certain services. I have spent hours on the phone with support only to find (on my own) that a particular URL was not accessible.
Having this utility made public and the first step to troubleshooting could alleviate many support requests and frustrations. The article below covers the majority of the URLs and ports that require whitelisting. I would also ask that this utility also addresses the “Anything else with a .sonos.com sub-domain” wildcard.
https://support.sonos.com/en-us/article/configure-your-firewall-to-work-with-sonos
