It sounds like you factory reset it - The solution is to just create a new Sonos System and add it to your existing Sonos account. You can always add it back to any ‘existing’ system later (if necessary) when you return Home.

If you need to use the Roam in Bluetooth mode later, then see this support link too…

https://support.sonos.com/en-us/article/pair-sonos-roam-with-bluetooth

Thanks Ken, tried that. Now won't connect to hotel wifi despite phone/network and passwords all entered correctly. The guess the roam isn't that great a travel speaker. It shouldn't be this tricky especially using Bluetooth. The roam is dead in the water. 

You can’t set up a Sonos speaker on a hotel network that’s designed for users not to “see” each other, which is necessary for the system to work. You need two phones, one for the app and the other one supplying the network.

If you indeed involuntary reset the Roam this might have a point by criticising the UI - which others have done before you. 

Yes, if you’ve no access to a WiFi network, other than subscriber WiFi, then just use a mobile hotspot for setup and switch to Bluetooth after that. Roam is a great portable speaker, but the issue in this instance is the device was factory reset, accidentally, or otherwise. Not sure I’ve ever reset a speaker accidentally, but that’s perhaps another story. 

My young grandson had this issue when away camping, only in his case, he had no yet (ever) setup the Roam that I got him for his Birthday. He was able to sort it by using a Hotspot. It’s fairly straightforward.