Brokers are required by law to "protect" traders from financially harming themselves by restricting the trades that can be made until the trader verifies that they know what they are doing. Some brokers will go as far as to personally call you up and give you an on-the-spot quiz about how options work before letting you trade them, for example.

Many brokers seem to have gotten very lax about this in recent years, and even Schwab/Ameritrade allowed me to trade options without verifying anything. My guess is that the recent Robinhhood/GME fiasco is going to see FINRA cracking down hard and reinstating some strict verification procedures.