Why is there an error when selling stocks?

According to the requirements of FINRA in the United States, any customer can only execute a maximum of 3 day trades within any consecutive 5 trading days. Otherwise, they will be marked as a "Pattern Day Trader" (PDT). If you engage in PDT behavior, any day trades beyond the third within 5 consecutive trading days will be rejected.

If you do not fall under the above circumstances and encounter an error when selling, please provide a screenshot to the customer service staff for further verification.