It doesn’t say it in the post but it’s what happened. “Your account was closed and we can’t tell you why, also you’re banned now” is always suspected fraud or worse.

Source: I work in fintech. Everyone who works in fintech knows this.

The "worse" has been proven to be political.. like when they closed gun dealers accounts a couple of years ago

While that sucks, my understanding is that was done differently. Those accounts were not locked and they told them a vague reason about risk. I believe they even gave them a month or so to withdraw before the accounts were to be closed.

If your account gets "flagged" and "locked" with no explaination at all, it's almost always suspected fraud, money laundering, or ties to blacklisted organizations.

I believe you are most likely right. I spoke with the teller at the bank and they said this happens most often with trying to cash bad checks. Mine is not that because I have never done that. My best guess with little evidence is some kind of anti money laundering thing, but again they won't say anything

If you don't know what happened, try to get a bank statement of the past ~2 months and go to someone who works in finance, ask them if there's anything that could raise red flags.