Official repositories not loading when upgrading

Hi guys, was trying to upgrade from 15.6.2 to 16.0.4 on my CentOS 7.7 machine but was unable to load the official repositories…

[xxx ~]$ sudo yum --showduplicates list gitlab-ce
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was
12: Timeout on http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras&infra=stock error was
12: Timeout on http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=extras&infra=stock: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=updates&infra=stock error was
12: Timeout on http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=updates&infra=stock: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
http://mirror.centos.org/centos/7/os/x86_64/repodata/repomd.xml: [Errno 12] Timeout on http://mirror.centos.org/centos/7/os/x86_64/repodata/repomd.xml: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
http://mirror.centos.org/centos/7/os/x86_64/repodata/repomd.xml: [Errno 12] Timeout on http://mirror.centos.org/centos/7/os/x86_64/repodata/repomd.xml: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
base                                                                                                                                                                                                                                                                     | 3.6 kB  00:00:00
docker-ce-stable                                                                                                                                                                                                                                                         | 3.5 kB  00:00:00
extras                                                                                                                                                                                                                                                                   | 2.9 kB  00:00:00
https://packages.gitlab.com/gitlab/gitlab-ce/el/7/x86_64/repodata/repomd.xml: [Errno 14] curl#35 - "TCP connection reset by peer"
Trying other mirror.


 One of the configured repositories failed (gitlab_gitlab-ce),
 and yum doesn't have enough cached data to continue. At this point the only
 safe thing yum can do is fail. There are a few ways to work "fix" this:

     1. Contact the upstream for the repository and get them to fix the problem.

     2. Reconfigure the baseurl/etc. for the repository, to point to a working
        upstream. This is most often useful if you are using a newer
        distribution release than is supported by the repository (and the
        packages for the previous distribution release still work).

     3. Run the command with the repository temporarily disabled
            yum --disablerepo=gitlab_gitlab-ce ...

     4. Disable the repository permanently, so yum won't use it by default. Yum
        will then just ignore the repository until you permanently enable it
        again or use --enablerepo for temporary usage:

            yum-config-manager --disable gitlab_gitlab-ce
        or
            subscription-manager repos --disable=gitlab_gitlab-ce

     5. Configure the failing repository to be skipped, if it is unavailable.
        Note that yum will try to contact the repo. when it runs most commands,
        so will have to try and fail each time (and thus. yum will be be much
        slower). If it is a very temporary problem though, this is often a nice
        compromise:

            yum-config-manager --save --setopt=gitlab_gitlab-ce.skip_if_unavailable=true

failure: repodata/repomd.xml from gitlab_gitlab-ce: [Errno 256] No more mirrors to try.
https://packages.gitlab.com/gitlab/gitlab-ce/el/7/x86_64/repodata/repomd.xml: [Errno 14] curl#35 - "TCP connection reset by peer"

Any idea to make it work? Or are there alternative ways to upgrade?

Thanks in advance.

Hi all, it was all due to some internal network issues which has now been resolved. Case closed.