Cannot update any packages. Yum doesn't work

Issue

• Issusing yum list command gives ssl error below:

File "/usr/share/rhn/up2date_client/up2dateAuth.py", line 139, in getLoginInfo
    login()
  File "/usr/share/rhn/up2date_client/up2dateAuth.py", line 98, in login
    li = server.up2date.login(systemId)
  File "/usr/share/rhn/up2date_client/rhnserver.py", line 64, in __call__
    raise up2dateErrors.SSLCertificateVerifyFailedError()
up2date_client.up2dateErrors.SSLCertificateVerifyFailedError: The SSL certificate failed verification.

• Trying to use http instead of https can register but now when trying to upgrade yum tools:

File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 530, in _loadRepoXML
    cache=self.http_caching == 'all')
  File "/usr/lib/yum-plugins/rhnplugin.py", line 209, in _getFile
    start, end, copy_local, checkfunc, text, reget, cache)
  File "/usr/lib/yum-plugins/rhnplugin.py", line 298, in _noExceptionWrappingGet
    return result
UnboundLocalError: local variable 'result' referenced before assignment