I installed a module and I cannot lock the version installed. It says 'stream not enabled', why do I have to enable a stream?

The steps I have performed:

[root@911c07d9279f /]# dnf install nodejs
(1/4): Copr repo for DNF-Modules owned by mhatina                                                                                              33 kB/s |  36 kB     00:01
(2/4): Modularity repo for modular defaults on Boltron.                                                                                        30 kB/s |  37 kB     00:01
(3/4): Fedora Modular 26 - x86_64                                                                                                             308 kB/s | 2.2 MB     00:07
(4/4): Fedora Modular rawhide 26 - x86_64                                                                                                     213 kB/s | 2.8 MB     00:13
Loading repositories.
Last metadata expiration check: 0:00:06 ago on Wed 30 Aug 2017 03:32:34 PM UTC.
Dependencies resolved.
==============================================================================================================================================================================
 Package                               Arch                        Version                                                  Repository                                   Size
==============================================================================================================================================================================
Installing:
 nodejs                                x86_64                      1:8.0.0-1.module_42d8f2a0                                fedora-modular                              5.8 M
Installing dependencies:
 compat-openssl10                      x86_64                      1:1.0.2j-6.module_836062be                               fedora-modular                              1.1 M
 gc                                    x86_64                      7.6.0-7.module_6faa4f4e                                  fedora-modular-rawhide                      110 k
 guile                                 x86_64                      5:2.0.14-1.module_39876f37                               fedora-modular                              3.5 M
 libatomic_ops                         x86_64                      7.4.4-2.module_39876f37                                  fedora-modular                               31 k
 libicu                                x86_64                      57.1-6.module_836062be                                   fedora-modular                              8.4 M
 libstdc++                             x86_64                      7.1.1-1.module_39876f37                                  fedora-modular                              456 k
 libtool-ltdl                          x86_64                      2.4.6-18.module_836062be                                 fedora-modular                               55 k
 libuv                                 x86_64                      1:1.11.0-1.module_836062be                               fedora-modular                              112 k
 make                                  x86_64                      1:4.2.1-2.module_39876f37                                fedora-modular                              493 k
Installing weak dependencies:
 npm                                   x86_64                      1:5.0.0-1.8.0.0.1.module_42d8f2a0                        fedora-modular                              3.4 M

Transaction Summary
==============================================================================================================================================================================
Install  11 Packages

Total download size: 23 M
Installed size: 81 M
Is this ok [y/N]: y
Downloading Packages:
(1/11): compat-openssl10-1.0.2j-6.module_836062be.x86_64.rpm                                                                                  414 kB/s | 1.1 MB     00:02
(2/11): libstdc++-7.1.1-1.module_39876f37.x86_64.rpm                                                                                          228 kB/s | 456 kB     00:02
(3/11): libuv-1.11.0-1.module_836062be.x86_64.rpm                                                                                              18 kB/s | 112 kB     00:06
(4/11): make-4.2.1-2.module_39876f37.x86_64.rpm                                                                                                31 kB/s | 493 kB     00:16
(5/11): libicu-57.1-6.module_836062be.x86_64.rpm                                                                                              299 kB/s | 8.4 MB     00:28
(6/11): gc-7.6.0-7.module_6faa4f4e.x86_64.rpm                                                                                                  34 kB/s | 110 kB     00:03
(7/11): libatomic_ops-7.4.4-2.module_39876f37.x86_64.rpm                                                                                       85 kB/s |  31 kB     00:00
(8/11): libtool-ltdl-2.4.6-18.module_836062be.x86_64.rpm                                                                                       24 kB/s |  55 kB     00:02
(9/11): nodejs-8.0.0-1.module_42d8f2a0.x86_64.rpm                                                                                             153 kB/s | 5.8 MB     00:39
(10/11): guile-2.0.14-1.module_39876f37.x86_64.rpm                                                                                            194 kB/s | 3.5 MB     00:18
(11/11): npm-5.0.0-1.8.0.0.1.module_42d8f2a0.x86_64.rpm                                                                                       215 kB/s | 3.4 MB     00:16
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                                         471 kB/s |  23 MB     00:50
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                                                                                      1/1
  Installing       : libstdc++-7.1.1-1.module_39876f37.x86_64                                                                                                            1/11
  Running scriptlet: libstdc++-7.1.1-1.module_39876f37.x86_64                                                                                                            1/11
  Installing       : libicu-57.1-6.module_836062be.x86_64                                                                                                                2/11
  Running scriptlet: libicu-57.1-6.module_836062be.x86_64                                                                                                                2/11
  Installing       : libtool-ltdl-2.4.6-18.module_836062be.x86_64                                                                                                        3/11
  Running scriptlet: libtool-ltdl-2.4.6-18.module_836062be.x86_64                                                                                                        3/11
  Installing       : libatomic_ops-7.4.4-2.module_39876f37.x86_64                                                                                                        4/11
  Running scriptlet: libatomic_ops-7.4.4-2.module_39876f37.x86_64                                                                                                        4/11
  Installing       : gc-7.6.0-7.module_6faa4f4e.x86_64                                                                                                                   5/11
  Running scriptlet: gc-7.6.0-7.module_6faa4f4e.x86_64                                                                                                                   5/11
  Installing       : guile-5:2.0.14-1.module_39876f37.x86_64                                                                                                             6/11
  Running scriptlet: guile-5:2.0.14-1.module_39876f37.x86_64                                                                                                             6/11
  Installing       : make-1:4.2.1-2.module_39876f37.x86_64                                                                                                               7/11
  Running scriptlet: make-1:4.2.1-2.module_39876f37.x86_64                                                                                                               7/11
  Installing       : compat-openssl10-1:1.0.2j-6.module_836062be.x86_64                                                                                                  8/11
  Installing       : libuv-1:1.11.0-1.module_836062be.x86_64                                                                                                             9/11
  Running scriptlet: libuv-1:1.11.0-1.module_836062be.x86_64                                                                                                             9/11
  Installing       : nodejs-1:8.0.0-1.module_42d8f2a0.x86_64                                                                                                            10/11
  Installing       : npm-1:5.0.0-1.8.0.0.1.module_42d8f2a0.x86_64                                                                                                       11/11
  Running scriptlet: guile-5:2.0.14-1.module_39876f37.x86_64                                                                                                            11/11
  Verifying        : nodejs-1:8.0.0-1.module_42d8f2a0.x86_64                                                                                                             1/11
  Verifying        : compat-openssl10-1:1.0.2j-6.module_836062be.x86_64                                                                                                  2/11
  Verifying        : libicu-57.1-6.module_836062be.x86_64                                                                                                                3/11
  Verifying        : libstdc++-7.1.1-1.module_39876f37.x86_64                                                                                                            4/11
  Verifying        : libuv-1:1.11.0-1.module_836062be.x86_64                                                                                                             5/11
  Verifying        : make-1:4.2.1-2.module_39876f37.x86_64                                                                                                               6/11
  Verifying        : guile-5:2.0.14-1.module_39876f37.x86_64                                                                                                             7/11
  Verifying        : gc-7.6.0-7.module_6faa4f4e.x86_64                                                                                                                   8/11
  Verifying        : libatomic_ops-7.4.4-2.module_39876f37.x86_64                                                                                                        9/11
  Verifying        : libtool-ltdl-2.4.6-18.module_836062be.x86_64                                                                                                       10/11
  Verifying        : npm-1:5.0.0-1.8.0.0.1.module_42d8f2a0.x86_64                                                                                                       11/11

Installed:
  nodejs.x86_64 1:8.0.0-1.module_42d8f2a0             npm.x86_64 1:5.0.0-1.8.0.0.1.module_42d8f2a0             compat-openssl10.x86_64 1:1.0.2j-6.module_836062be
  gc.x86_64 7.6.0-7.module_6faa4f4e                   guile.x86_64 5:2.0.14-1.module_39876f37                  libatomic_ops.x86_64 7.4.4-2.module_39876f37
  libicu.x86_64 57.1-6.module_836062be                libstdc++.x86_64 7.1.1-1.module_39876f37                 libtool-ltdl.x86_64 2.4.6-18.module_836062be
  libuv.x86_64 1:1.11.0-1.module_836062be             make.x86_64 1:4.2.1-2.module_39876f37

Complete!

[root@911c07d9279f /]# dnf module lock nodejs
Loading repositories.
Last metadata expiration check: 0:03:14 ago on Wed 30 Aug 2017 03:35:14 PM UTC.
Error: Stream not enabled. Skipping 'nodejs'