I saw the same yesterday evening.
I just tried again today and the same error persists.
[root@Nethserver ~]# yum repolist -v
Loading "changelog" plugin
Loading "fastestmirror" plugin
Loading "nethserver_events" plugin
Config time: 0.015
Yum version: 3.4.3
Loading mirror speeds from cached hostfile
Setting up Package Sacks
pkgsack time: 0.010
Repo-id : sb-base/x86_64
Repo-name : Stable mirror: CentOS Base 7
Repo-revision: 1525378614
Repo-updated : Thu May 3 13:17:37 2018
Repo-pkgs : 9,911
Repo-size : 8.2 G
Repo-mirrors : https://mirrorlist.nethserver.com/?repo=base&arch=x86_64&nsversion=7.5.1804&usetier=$YUM0
Repo-baseurl : https://m1.nethserver.com/stable/7.5.1804/base/x86_64/
Repo-expire : 7,200 second(s) (last: Wed Nov 28 09:27:27 2018)
Filter : read-only:present
Repo-filename: /etc/yum.repos.d/subscription.repo
Repo-id : sb-centos-sclo-rh/x86_64
Repo-name : Stable mirror: SCLo rh 7
Repo-revision: 1541456160
Repo-updated : Mon Nov 5 14:18:13 2018
Repo-pkgs : 8,099
Repo-size : 7.3 G
Repo-mirrors : https://mirrorlist.nethserver.com/?repo=centos-sclo-rh&arch=x86_64&nsversion=7.5.1804&usetier=$YUM0
Repo-baseurl : https://m1.nethserver.com/stable/7.5.1804/centos-sclo-rh/x86_64/
Repo-expire : 7,200 second(s) (last: Wed Nov 28 09:27:28 2018)
Filter : read-only:present
Repo-filename: /etc/yum.repos.d/subscription.repo
Repo-id : sb-centos-sclo-sclo/x86_64
Repo-name : Stable mirror: SCLo sclo 7
Repo-revision: 1538384702
Repo-updated : Mon Oct 1 02:05:07 2018
Repo-pkgs : 775
Repo-size : 241 M
Repo-mirrors : https://mirrorlist.nethserver.com/?repo=centos-sclo-sclo&arch=x86_64&nsversion=7.5.1804&usetier=$YUM0
Repo-baseurl : https://m1.nethserver.com/stable/7.5.1804/centos-sclo-sclo/x86_64/
Repo-expire : 7,200 second(s) (last: Wed Nov 28 09:27:28 2018)
Filter : read-only:present
Repo-filename: /etc/yum.repos.d/subscription.repo
Repo-id : sb-epel/x86_64
Repo-name : Stable mirror: EPEL 7
Repo-revision: 1542594245
Repo-updated : Sun Nov 18 20:40:12 2018
Repo-pkgs : 12,706
Repo-size : 14 G
Repo-mirrors : https://mirrorlist.nethserver.com/?repo=epel&arch=x86_64&nsversion=7.5.1804&usetier=$YUM0
Repo-baseurl : https://m1.nethserver.com/stable/7.5.1804/epel/x86_64/
Repo-expire : 7,200 second(s) (last: Wed Nov 28 09:27:29 2018)
Filter : read-only:present
Repo-filename: /etc/yum.repos.d/subscription.repo
Repo-id : sb-extras/x86_64
Repo-name : Stable mirror: CentOS Extras 7
Repo-revision: 1541683984
Repo-updated : Thu Nov 8 05:36:55 2018
Repo-pkgs : 434
Repo-size : 806 M
Repo-mirrors : https://mirrorlist.nethserver.com/?repo=extras&arch=x86_64&nsversion=7.5.1804&usetier=$YUM0
Repo-baseurl : https://m1.nethserver.com/stable/7.5.1804/extras/x86_64/
Repo-expire : 7,200 second(s) (last: Wed Nov 28 09:27:29 2018)
Filter : read-only:present
Repo-filename: /etc/yum.repos.d/subscription.repo
Repo-id : sb-nethserver-base/x86_64
Repo-name : Stable mirror: NethServer Base 7
Repo-revision: 1528711431
Repo-updated : Mon Jun 11 03:03:55 2018
Repo-pkgs : 283
Repo-size : 1.0 G
Repo-mirrors : https://mirrorlist.nethserver.com/?repo=nethserver-base&arch=x86_64&nsversion=7.5.1804&usetier=$YUM0
Repo-baseurl : https://m1.nethserver.com/stable/7.5.1804/nethserver-base/x86_64/
Repo-expire : 7,200 second(s) (last: Wed Nov 28 09:27:30 2018)
Filter : read-only:present
Repo-filename: /etc/yum.repos.d/subscription.repo
Repo-id : sb-nethserver-updates/x86_64
Repo-name : Stable mirror: NethServer Updates 7
Repo-revision: 1542615150
Repo-updated : Mon Nov 19 00:12:45 2018
Repo-pkgs : 334
Repo-size : 1.1 G
Repo-mirrors : https://mirrorlist.nethserver.com/?repo=nethserver-updates&arch=x86_64&nsversion=7.5.1804&usetier=$YUM0
Repo-baseurl : https://m1.nethserver.com/stable/7.5.1804/nethserver-updates/x86_64/
Repo-expire : 7,200 second(s) (last: Wed Nov 28 09:27:30 2018)
Filter : read-only:present
Repo-filename: /etc/yum.repos.d/subscription.repo
Repo-id : sb-updates/x86_64
Repo-name : Stable mirror: CentOS Updates 7
Repo-revision: 1540837319
Repo-updated : Mon Oct 29 11:33:45 2018
Repo-pkgs : 1,613
Repo-size : 5.7 G
Repo-mirrors : https://mirrorlist.nethserver.com/?repo=updates&arch=x86_64&nsversion=7.5.1804&usetier=$YUM0
Repo-baseurl : https://m1.nethserver.com/stable/7.5.1804/updates/x86_64/
Repo-expire : 7,200 second(s) (last: Wed Nov 28 09:27:31 2018)
Filter : read-only:present
Repo-excluded: 1
Repo-filename: /etc/yum.repos.d/subscription.repo
repolist: 34,155
[root@Nethserver ~]#
Cheers.