None of the Ambari archive repo link now working.Though username and password is correct, we are getting "403 Forbidden (varnish) the provided credentials were incorrect"
Just to expand a bit on what @Daming Xue wrote above, the reason your username and password are probably not working is because you're not using the correct set of credentials.
The credentials to access the private repository where Cloudera is now distributing previous versions of Ambari are not are not generally the same ones to access Cloudera's website or the Cloudera community. People with a valid Cloudera subscription can obtain their repository credentials by opening a non-technical case within the support portal.
If your organization does not already have a valid Cloudera subscription, then you'll have to begin that process by contacting the Cloudera Sales Team to find out more about subscription options.
@ask_bill_brooks I have a related issue and I have contacted the Sales Team multiple times over the last two weeks and still no response. What should the next steps be to get some help in order to obtain the necessary credentials?