How to get username and password in documentation ambari 2.7.5

[#1]

https://docs.cloudera.com/HDPDocuments/Ambari-2.7.5.0/bk_ambari-installation/content/ch04s03s05.html

I read above documentaion and 
I don't understand how to input username and password.
I tried to input my cloudera username and password but it resulted 403 forbidden

https://username:password@archive.cloudera.com/p/ambari/ubuntu18/2.x/updates/2.7.5.0/ambari.list

 
Please give me username and password.
If cannot, please tell me how can I contact cloudera using e-mail.

[#2 · Accepted solution]

Starting from Ambari 2.7.5 the repositories require username and password that you get from Cloudera if you have a required support contract.  Existing users can file a non-technical case within the support portal (https://my.cloudera.com) to obtain credentials. You can find more information on Accessing Ambari Repositories page. 

[#3]

Hello,

I'm trying to open a non-technical case to get username and password as suggested in the guide:

https://docs.cloudera.com/HDPDocuments/Ambari-2.7.5.0/bk_ambari-installation/content/ch03s02s01.html

but when i click on "Create Case" button, I got the error: "Accessing the requested page requires special permissions."

So, anyone can tell me how to contact Cloudera to get the credential needed?

Thank You