source package download fail for rhel 6

Hello!

I`m getting the following error when trying to install source package. 
Maybe I`m doing something wrong?

# cat /etc/redhat-release
Red Hat Enterprise Linux Server release 6.9 (Santiago)

# rpm -ivh 
https://download.postgresql.org/pub/repos/yum/reporpms/EL-6-x86_64/pgdg-redhat-repo-latest.noarch.rpm
Retrieving 
https://download.postgresql.org/pub/repos/yum/reporpms/EL-6-x86_64/pgdg-redhat-repo-latest.noarch.rpm
warning: /var/tmp/rpm-tmp.hTDjuz: Header V4 DSA/SHA1 Signature, key ID 
442df0f8: NOKEY
Preparing... ########################################### [100%]
    1:pgdg-redhat-repo ########################################### [100%]

# yum install postgresql10-server
...
Complete!

# yumdownloader --source postgresql10
Loaded plugins: ovl, product-id
Enabling pgdg95-source repository
Enabling pgdg96-source repository
Enabling pgdg12-source repository
Enabling pgdg94-source repository
Enabling pgdg11-source repository
Enabling rhel-6-server-source-rpms repository
Enabling pgdg10-source repository
....
https://download.postgresql.org/pub/repos/yum/srpms/12/redhat/rhel-6Server-x86_64/repodata/repomd.xml: 
[Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not 
Found"
Trying other mirror.
To address this issue please refer to the below knowledge base article

https://access.redhat.com/articles/1320623

If above article doesn't help to resolve this issue please open a ticket 
with Red Hat Support.

Cannot retrieve repository metadata (repomd.xml) for repository: 
pgdg12-source. Please verify its path and try again

-- 
Grigory Smolkin
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company