Problems with SQLNCLI connection string

We have fresh installation of SQL Server 2012 on WIN2012 64 bit. According to ODBC Administrator, SQL Server native Client 11.0 is installed, too.

However, while trying to connect to SQL with "Provider=SQLNCLI..." or "Provider=SQLNCLI11..." or "Provider="SQLNCLI11.0...", we receive an error:

ADODB.Connection error '800a0e7a' Provider cannot be found. It may not be properly installed.
Our webpage is in classic ASP, app.pool enable 32-bit applictions is True, Managed pipeline is Classic.

Interesting, while we try to connect to the same SQL with OLEDB, t.i. "Provider=SQLOLEDB..." everything works just fine.

Any ideas?

Looks all right to me, but this site has the complete A-to-Z of connection strings, so it might be worth double checking if they say anything which is different to what you are doing already:

https://www.connectionstrings.com/sql-server-2012/

Sounds like your APP is running on the same box as SQL? but if not the SQL Client also needs to be run on the Client machine(s).

You can check which version is installed, on the machine where the APP is running, by looking in the registry. I only have the setting for V.10, but presumably V.11 is similar:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\SQLNCLI10\CurrentVersion

Problem solved:
We have SQLNCLI on SQL server only, and NOT on our WEB server, which wants to connect to SQL.
After we installed SQLNCLI on our WEBSERVER, connection succeeded.