I heard a lot about that a few months ago, but they've improved their detection algorithm since then. You can try emailing support and ask to be whitelisted, but past that I'm not sure if there's anything you can do. I've never had that problem with them, so I didn't look too closely into the resolution of it back when it was more common. If you do a few searches for "coinbase high risk" you may be able to find something useful however.
Just did google search for the keywords you wrote. Didn't expect to see so many negative feedbacks 
I'm not alone with this. And who is Olaf? There was a message that he can help me.A lot of people were getting hit with high-risk transaction failures a few months ago, hence the number of search results. /u/-Olaf- on Reddit is on Coinbase's support team, he was whitelisting people with issues back then but his account seems inactive now since he hasn't posted anything in about a month. Sending support an email requesting to be whitelisted is most likely the best (and fastest) option, though it may take a day or two depending on their response time.