Printer works, but the scanner doesn't
This is a useful clue. Since printing still works, leave the printer's Wi-Fi and basic setup alone for now and focus on scanning.
1. See whether Windows can find the scanner
Open Settings → Bluetooth & devices → Printers & scanners, select the printer, and look for Scanner settings.
2. Try a scanning program you already have
That might be Windows Fax and Scan, Scan, or the printer maker's scanning app. If it sees the scanner, try one page.
3. If one scanning program works
The scanner itself is working. Check the program that fails and make sure it has the correct scanner selected.
4. If Windows cannot find the scanner
USB: check the cable. If this started recently while printing still works, see the USB scanner missing guide.
Wi-Fi/network: make sure the computer and printer are on the same network.
5. Only then look at printer software
Use Windows Update or the printer manufacturer's official support page. Avoid driver-updater ads or remote-support downloads.
If you do not have a scanning program
That does not mean the scanner is broken. Microsoft's Scan app may not already be installed, and many printer makers provide their own scanning app.