identity.apple.com/pushcert not loading
It's not loading for me either on my Mac in the US. However, if you request directly to https


https://identity.apple.com/pushcert/ - works for me
http://identity.apple.com/pushcert/ - fails without much of an error message


If you need the non-https link to work or both are failing for you, I would perhaps try on a mobile network just to make sure it's not a routing issue between your ISP and Apple. Mobile safari should work to test the connection and it gives a more friendly user error message IMO.


https://developer.apple.com/system-status/
https://www.apple.com/support/systemstatus/


Since you have an issue that's not covered, I would open an actual ticket with main support and ask them if you need to contact developer support instead for the push cert renewal.