Lose > lost; inability to find

Loose > opposite of tight

Loosing > not a word

Losing > what you meant

We have covered this many times before, so please fix your post before the internet is irreparably damaged 

Probably duplicate IP addresses due to the router change.   These will cause sporadic connections, disappearing components, etc. To solve, reboot/power cycle each of these in order:

Modem
Router
Hubs or switches
Wired Sonos components
Wireless Sonos components
Computers, printers
Phones, tablets, all other wireless devices

Note you can prevent duplicate IP addresses by reserving a permanent IP for each Sonos unit in your router setup. See your router manual for details.

Unlikely, but you could do a quick and dirty test by connecting one of your PLAY:1s to your router with an Ethernet cable. It then becomes the same thing as a BOOST, just with the Speaker attached. 

What I’d suggest, especially after changing your Wi-Fi, is a network refresh. Unplug or power down all your Sonos devices. And I mean a full power off, not just ‘sleep’ for the Roam. While they’re off, reboot your router. Give the router a couple of minutes to come back up, then plug back in your Sonos devices, and power up the Roam. 

I think that will help. If it doesn’t, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

Edit: essentially the same response as @jgatie above, I just type more slowly.