SQL Server 2016 R Services. Error in connection

I've previously installed SQL Server 2016, and want to try its R Services. I went through this tutorial and came to Step 2.5, where I had to test connection by this script:

exec sp_execute_external_script  @language =N'R',  
@script=N'OutputDataSet<-InputDataSet',    
@input_data_1 =N'select 1 as hello'  
with result sets (([hello] int not null));  
go  

Error is:

Msg 39021, Level 16, State 1, Line 1
Unable to launch runtime for 'R' script. Please check the configuration of the 'R' runtime.
Msg 39019, Level 16, State 1, Line 1
An external script error occurred: 
Unable to launch the runtime. ErrorCode 0x80070490: 1168(Element not found.).

I've googled, and this tutorial states that I have to uninstall and then install RegisterRExt.exe. I did that. Restarted computer and instance services. But error continues to come.

How can I fix it?