Ubuntu 18.04.1では、Systemdが「/user.slice/...service/init.scope制御グループを作成できませんでした：権限が拒否されました」で失敗します。

私のUbuntu 18.04.1システムでは、systemdのユーザーマネージャが起動しません。私はこれが私が現在経験している他の問題の根本的な原因だと思います。これを削除する方法についてのアイデアはありますか？

システムバージョン

$ systemd --version
systemd 237
+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN2 +IDN -PCRE2 default-hierarchy=hybrid

Ubuntu 18.04.1 LTSバージョン

$ uname -a
Linux example.com 4.15.0 #1 SMP Wed Jul 25 19:09:31 MSK 2018 x86_64 x86_64 x86_64 GNU/Linux

systemctl デバイスの状態

 $ sudo systemctl status [email protected]
● [email protected] - User Manager for UID 1001
   Loaded: loaded (/lib/systemd/system/[email protected]; static; vendor preset: enabled)
  Drop-In: /lib/systemd/system/[email protected]
           └─timeout.conf
   Active: failed (Result: protocol) since Tue 2019-01-08 10:33:08 CET; 1min 42s ago
  Process: 315 ExecStart=/lib/systemd/systemd --user (code=exited, status=1/FAILURE)
 Main PID: 315 (code=exited, status=1/FAILURE)

Jan 08 10:33:08 example.com systemd[1]: Starting User Manager for UID 1001...
Jan 08 10:33:08 example.com systemd[315]: pam_unix(systemd-user:session): session opened for user mischa by (uid=0)
Jan 08 10:33:08 example.com systemd[1]: [email protected]: Failed with result 'protocol'.
Jan 08 10:33:08 example.com systemd[1]: Failed to start User Manager for UID 1001.

システムログによると

Jan  8 10:33:08 example.com systemd[1]: Starting User Manager for UID 1001...
Jan  8 10:33:08 example.com systemd[315]: Failed to create /user.slice/user-1001.slice/[email protected]/init.scope control group: Permission denied
Jan  8 10:33:08 example.com systemd[315]: Failed to allocate manager object: Permission denied
Jan  8 10:33:08 example.com systemd[1]: [email protected]: Failed with result 'protocol'.
Jan  8 10:33:08 example.com systemd[1]: Failed to start User Manager for UID 1001.

マイユーザーサービスユニットファイル

$ cat /lib/systemd/system/[email protected]
#  SPDX-License-Identifier: LGPL-2.1+
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

[Unit]
Description=User Manager for UID %i
After=systemd-user-sessions.service

[Service]
User=%i
PAMName=systemd-user
Type=notify
ExecStart=-/lib/systemd/systemd --user
Slice=user-%i.slice
KillMode=mixed
Delegate=pids cpu
TasksMax=infinity
TimeoutStopSec=120s