If issue still persist then there might be a chance that some third party services/startups/application or security software is restricting it to get added.
So, I would suggest you to perform clean boot and
disable security software temporarily and then try to add printer.
Perform Clean Boot
Putting your system in Clean Boot state helps in identifying if any third party applications or startup items are causing the issue. You need to follow the steps from the article mentioned below to perform a Clean Boot.
Note: Refer "How to reset the computer to start normally after clean boot troubleshooting" to reset the computer to start as normal after troubleshooting.
Disable anti-virus temporarily.
Note: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have
to temporarily disable it to install other software, you should re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.
Now try to add the printer again by following the steps provided in the link mentioned below.