Getting 403 Forbidden for some reason

I am trying to submit the following market order

{“symbol”: “CDAK”, “notional”: “16666.6666666667”, “side”: “buy”, “type”: “market”, “time_in_force”: “day”}

Getting 403 Forbidden and the following response headers.

I thought maybe it has something to do with fractional amount in notional field, but it works just fine with other tickers.

Any ideas?

Thanks a lot.

Date: Fri, 31 Mar 2023 14:31:04 GMT
Content-Type: application/json; charset=UTF-8
Content-Length: 64
Connection: close
Access-Control-Allow-Origin: *
Vary: Origin
X-Ratelimit-Limit: 200
X-Ratelimit-Remaining: 199
X-Ratelimit-Reset: 1680273064
X-Request-Id: 40fee3323088c57de1d63c23c2f7a1e2
Strict-Transport-Security: max-age=31536000; includeSubDomains
Access-Control-Allow-Credentials: true
Access-Control-Allow-Methods: GET, OPTIONS, PUT, DELETE, POST, PATCH
Access-Control-Allow-Headers: Apca-Api-Key-Id, Apca-Api-Secret-Key, Authorization
Access-Control-Max-Age: 1728000

I have to mention that I have sufficient buying power. The issue seem to happen with some tickers and not with others.

This seems to happen with some limited set of tickers like BRDS, SCYX, CDAK…The orders for others work just fine.

Really lost here…Please advice.

Okay, got the answer. The reason is these tickers do not allow fractional shares, and when notional is used thats exactly what is happening. So if you want a market order, use qty instead.