If you see these type of errors in IE you can press F12 to see the errors.
Chrome/Firefox can also show HTTP message details.
I am also seeing errors in the new portal.
I was trying to see azure website and I saw "error loading part" errors.
Microsoft_Azure_Billing] 9:30:19 AM MsPortalFx.Base.Diagnostics.ErrorReporter 2 message: Access is denied.
[WebsitesExtension] 9:30:19 AM MsPortalFx.Base.Diagnostics.ErrorReporter 2 message: Access is denied.
New portal is in preview but is no longer optional as many of the services are only available in the new portal. Azure support should be informed to make them aware of this issue.