It's really weird , on their page here :
https://coinbase.statuspage.io/ It says that everything is working just fine but the page in other hand isn't loading .
I get (from your link):
Coinbase website and API - unplanned outage
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Investigating - Our team is currently investigating unplanned downtime. The
www.coinbase.com website and the Coinbase API and Merchant platform are both currently offline.
Apr 20, 10:26 PDT