Have you first removed the old WiFi network and then added the new VM SSID/Password to the Arc? If not, see this link:

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

Hi I've reset to factory setting so starting fresh just see arc when I install new device but when it comes to adding WiFi I get WiFi password error I now it's OK all my other devices work just cannot get arc to connect for some reason 

Strange, I have used the new Virgin Media v5 Hub in the past and it worked okay here with the Sonos Arc? Have you considered factory resetting the Hub itself?

I'll try it at weekend hopefully it connect just cannot workout why I keep getting error 

Got home early so tryed to factory resetting router i thought when you reset router back to factory setting remove all devices but this virgin hub connect everything back up and no password needed for reconnect devices phoned virgin and they not helpfull at all and still password on sonos ark says wrong password only divice that dosent connect to hub and help 

The ‘default’ password for the WiFi is on the plastic card that slots into the top slot on the rear of the v5 router - slide out the card to get the password - assuming you have not changed it …and then setup the Arc using the SSID and that WiFi password.

Hi that's the password iam useing and it says password wrong the virgin engineer set it up once cause it was working I took arc down of wall wall when painting and it never connected again I've reset arc but wondering if old setting for arc still in router that's why it not connecting or I might be miles away in thinking that it's been a strange one just wish it was easy to just connect  

If you reset the router/password then it should be the one that’s on the card I mentioned - but have you tried adding the router credentials to the Arc over .BLE - simply goto "networks/update networks” in the Sonos App and add the router credentials directly to the Sonos Arc.

I tryed to update network but it dosent see arc in app just the to sl surround  speakers not sure if it cause I've hard reset it or not 

After you factory reset the Arc, the status LED flashes amber and a short while later it switches to flashing green and is then ready for setup.

In that situation, you need to open the Sonos App and you will either be prompted to setup the speaker or you can use the ‘Add Product’ option in ‘Settings/System’. If that’s what you’re doing and it’s still not working for you then perhaps try cabling the speaker to the local network temporarily, but make sure you see your other (One SL) speakers in the Sonos App first before adding your Arc to the system. (Do not create a new Sonos system).

In network settings in the Sonos App you should also see the WiFi network SSID listed under networks. If there are other older WiFi networks you can select to remove those, if no longer required.

If the problems still persist, then it maybe best to reproduce the issue(s) seen and immediately submit a Sonos system diagnostic report from within the Sonos App, note it’s reference and contact/chat with Sonos Support Staff via this LINK and see what the Staff can perhaps suggest to help you to resolve the matter.

Hi thanks for all the help after all banging my head against wall and keep getting error I thought tryed another phone and download a fresh sonos app and worked first time must be something stored in app stopping me trying to log into WiFi but glad I've got it working tv or never the same .....lol