ODBC Connection via MS Access does not work

Hi,

I have set up a server with windows 2016 and sql server express 2014.

I have clients which shall use additional ms access requests via odbc connection.

The manually setup odbc connection with sql client v11 works fine, when I test it with the ODBC-configurator.

When the ms access programs try to use it, I end up with the following error message:(translated to english, maybe not 100% correct)

SQLState '08001'

SQL Server-Error: -1

[Microsoft][SQL Server Native Client 11.0]SQL Server Networkinterface:Error searching the defined server/instance [xFFFFFFFF]

Error of connection:

SQLState 'S1T00'

SQL Server Error:0

[Microsoft][SQL Server Native Client 11.0]Timeout

Any ideas what I can do?

Thanks very much in advance

H. Hidden