Sounds like you have a Sonos device Ethernet wired to your router.  If so disconnect it and connect everything to WiFi.

No. I don't have an Ethernet cable to try that option, so... Not connected.

 Then what is the “temporary WiFi of Sonos”?  I thought maybe that meant SonosNet.  I was not suggesting you Ethernet a speaker.  Actually just the opposite.  Keep all of the Sonos devices on WiFi.

 What is your network makeup?  Is your WiFi broadcasting only one SSID?  Has the Play 1 ever been connected to WiFi in your home?  Is the Play 1 a new acquisition?  When the Play 1 is reset is the LED flashing green?

@SarahDianne,

In your opening post you start off by saying ”I’ve reset…” Can I first ask what you reset? Was it your speaker, router, or your Sonos App? It sounds like you are attempting to connect a speaker that’s already setup in a Sonos ‘Household’ to a different, or reset, WiFi network. 

As a quick test to see if that’s the case, you could temporarily wire the speaker to the local router and see if a ‘reset’ Sonos App connects to the ‘existing’ Sonos system and then go from there, but it really all depends on what you may have ‘reset’ in the first instance.

I reset the speaker to factory. Followed steps to switch to new wifi. 

I have 1 speaker the Play 1. Everything is going normally except that it tells me that my wifi password is wrong. What I am entering is 100% not wrong. It keeps connecting to a temporary sonos wifi which I don't recall it has done before. 

I've moved,  changed wifi, taken the speaker different places to use. I've never had an issue getting it set up. I will have to call them I guess.

Okay, as you have factory reset your one and only speaker, you also need to reset the Sonos App too, or remove and reinstall the App from this LINK and choose the first option to setup a ‘Speaker or Component’. See screenshot.

Post-reset ensure your speaker status LED is flashing green (if not, reset it again following the instructions HERE). Just ensure the new routers WiFi is 802.11b/g/n backward compatible using security mode WPA2 personal for compatibility. Also check your mobile device meets these requirements…

https://support.sonos.com/en-us/article/sonos-app-requirements

See if that suggestion works for you.

I removed and reinstalled the app and the Sonos app accepted my wifi password... Finally! Yay

Had a couple issues connecting to the speaker afterwards but I was able to sort it out. 

Thanks for your help folks!

I confirm that the problem is on the app.

I had exactly the same issue and after hours of exploring wifi settings and changing passwords I had the idea of installing the sonos app on another android device. Password accepted on the new device and everything worked as intended.

I don’t follow the logic. It works on one device, but not on another? Doesn’t that suggest it is a device issue, not an app issue?

Maybe the app is buggy on some Android versions. The password didn't work on the phone with latest Android and it worked on the phone with older Android.

I was adding two speakers.

Uninstalling and reinstalling the app worked for the first one. The second one would fail again getting the right network so I tried again uninstalling and reinstalling the app, but didn’t work.
I had to unplug and plug it back in and that worked.

Spent a good two hours with all this doing my head in. Not nice.

I think there may be Android bugs, not wanting to call support I tried to work around them.

Best suggestion was to “force stop” the Sonos App. That seemed to work for my issues but I can never remember how to do it.

Dumb, but faster than looking up how to force stop for my old brain is just to reboot the Controller’s device.