"Coinbase has come under fire in recent weeks for slow transaction times, nonexistent support, and multiple server outages under high traffic. The US-based exchange even suspended trading when things really got lively during Litecoin’s romp to the top a few days ago. However new things could be coming to Coinbase in 2018."
http://bitcoinist.com/altcoins-coming-coinbase-says-ceo-brian-armstrong/