Your Phone app in Windows 10 can now use wallpaper from your phone  

Nope, nothing, that didn't work. The app is completely dead. Even the new version installed yesterday doesn't fix it.

Open the Windows 10 Settings App and navigate to Update & Security > Troubleshoot.
On the right side panel, you will find various troubleshooters.

Locate Windows Store Apps Troubleshooter, and run it.
Follow the on-screen instructions,
and it will fix common problems around the app. Once complete launch the app, and check if the issue exists.

If still have the issue try the following

Unlink and link your devices
Open Windows 10 Settings > Phone > Unlink this PC.

On your PC Go, accounts.microsoft.com/devices, and sign in with your Microsoft account.
Go to Devices page > Show details > More actions > Unlink this phone.

Now link your devices again.

Open the Windows 10 Settings App and navigate to Apps > Apps & Features.
On the right-side panel, look out for the entry of Your Phone.
Select it and then select Advanced options.
Under the section of Reset, click on the button that says Reset.

Then try - connecting and setting up Your Phone

I don't know what else to suggest if you still having the issue
Are you sure your phone is compatible - an Android phone

xsteveuk said:

Open the Windows 10 Settings App and navigate to Update & Security > Troubleshoot.
On the right side panel, you will find various troubleshooters.

Locate Windows Store Apps Troubleshooter, and run it.
Follow the on-screen instructions,
and it will fix common problems around the app. Once complete launch the app, and check if the issue exists.

If still have the issue try the following

Unlink and link your devices
Open Windows 10 Settings > Phone > Unlink this PC.

On your PC Go, accounts.microsoft.com/devices, and sign in with your Microsoft account.
Go to Devices page > Show details > More actions > Unlink this phone.

Now link your devices again.

Open the Windows 10 Settings App and navigate to Apps > Apps & Features.
On the right-side panel, look out for the entry of Your Phone.
Select it and then select Advanced options.
Under the section of Reset, click on the button that says Reset.

Then try - connecting and setting up Your Phone

I don't know what else to suggest if you still having the issue
Are you sure your phone is compatible - an Android phone

I have a Samsung Galaxy S9+. I've done everything you suggested but no luck. It was working until I did an in-place upgrade to fix something else, it hasn't worked since.

I give up with it now.