Just to follow-up. I tried to purchase 1 BTC yesterday from Coinbase and was also denied with the same explanation as before. At this point I have to assume it's my bank that is causing the issue- as was mentioned earlier.
It is for sure your bank. A week or two ago for shoots and giggles I tested purchases of $3 and sells of $3 and it went through successfully.
Credit Unions are your solution.