Too many cash deposits? Out of state deposits?
But then again, I've also had good luck with Chase and Wells Fargo, the only difference being that those were well established accounts.
Edit: FinCEN and other govt. agencies have published guidelines (intended for banking compliance) on how to detect money laundering and transaction structuring patterns. You should read these so as to understand what kind of triggers the banks might have put in place ... and to avoid tripping them.
Sometimes it can just be down to "suspicious activity", which is ominous and ridiculously large 'definition' to it. I guess some banks just won't like Bitcoin or are suspicious of money laundering.