Hi.
I change the following Registry values
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Search]
"CortanaConsent"=dword:00000001
from 1 to 0 and back again to 1.
And I insert the key "BingSearchEnabled"=dword:00000000
The search bar now is working normally.
You can see the instructions in:
My windows is Windows 10 Pro 1909.
Kind regards
Paulo