See if the information in the below link helps to get the Roam on the new WiFi network:

https://support.sonos.com/en-us/article/connect-sonos-to-a-new-router-or-wi-fi-network

If the difficulties continue for any reason however, then perhaps if you have a second mobile device available, first set that up temporarily as a ‘WiFi hotspot’ mimicking your previous ‘case sensitive’ WiFi credentials (SSID/Password) and connect your Roam & the separate mobile controller device to that hotspot …then go through the ‘Update Networks’ feature in the Sonos App… that usually works every-time for most users if they encounter any difficulty connecting their controller device to their Roam hotspot for the BLE transfer of the new routers credentials.

Hope that assists.