After the September 2021 Windows Update, non-administrator users will no longer be able to add remote printers without an elevation of privilege to administrator.
To allow normal users to add remote printers (hosted on a print server), you can now add the following Registry value on the client:
HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Printers\PointAndPrint RestrictDriverInstallationToAdministrators = 0 (DWORD 32)
No restart of the client is needed.
If things still do not work, add the following Registry entry on the print server:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Print RpcAuthnLevelPrivacyEnabled = 0 (DWORD 32)
Then restart the Print Spooler service.
Please be aware that both Registry entries (set to "0") weaken the security. You should set them to "1" as soon as you can.