It's all dude to network load. Increase your gas prices and wei. That's the same thing as paying a fee on the Bitcoin network. The more people that use it, the more the fees will be. If you're having issues with transactions failing, it's more than likely you set your fees way too low.
The day before yesterday I wanted to send some tokens to hitbtc.
I used 3 Gwei (Gas Price) and 200,000 as Gas limit. It took more than 30 mins to show up with the tx and it was saying that the transaction needs around 15hrs to confirm.
When I logged in after 15hrs, the transaction was canceled... then I checked gas station for the recommended price and it was 9 Gwei.
For my stupidity, I lost over $300 profit from one of my investment. I was waiting over 4 months for the price to go up for that particular token. I got busted!