PostgrSQL Create extension timescale

hi i just can't install the timescaledb Extension in PostgreSQL.

CREATE EXTENSION timescaledb
    VERSION "1.6.0";

after saving; the message "Connection to Server has been lost"

Google did not help; already trying for Hours... Help!!!!

== Saving changes to: C:\Program Files\PostgreSQL\11\data\postgresql.conf
2020/03/18 21:39:26 Installing TimescaleDB library files...
2020/03/18 21:39:26 Success!
2020/03/18 21:39:26 Installing TimescaleDB control file...
2020/03/18 21:39:26 Success!
2020/03/18 21:39:26 Installing TimescaleDB SQL files...
2020/03/18 21:39:26 Success!
TimescaleDB installation completed successfully.

trying to create the Extension in the Shell gave me:

localdb=# CREATE EXTENSION IF NOT EXISTS timescaledb CASCADE;
FATAL:  extension "timescaledb" must be preloaded
TIP:  Please preload the timescaledb library via shared_preload_libraries.

This can be done by editing the config file at: C:/Program Files/PostgreSQL/11/data/postgresql.conf
and adding 'timescaledb' to the list in the shared_preload_libraries config.
        # Modify postgresql.conf:
        shared_preload_libraries = 'timescaledb'

Another way to do this, if not preloading other libraries, is with the command:
        echo "shared_preload_libraries = 'timescaledb'" >> C:/Program Files/PostgreSQL/11/data/postgresql.conf

(Will require a database restart.)

but shared_preload_libraries = 'timescaledb' is addet to the list…

postgresql.conf-file:

# - Shared Library Preloading -

shared_preload_libraries = 'timescaledb'    

#local_preload_libraries = 'timescaledb'
#session_preload_libraries = 'timescaledb'
#jit_provider = 'llvmjit'       # JIT library to use

# - Other Defaults -

#dynamic_library_path = '$libdir'

What am i doing wrong here ????