Regardless of the reason your account was restricted, the only way to get out of this restriction zone is by contacting bet365's customer support. Even if you have no idea why your account has been restricted, you should still contact customer support to get an idea so you can open it back.

Winning too much\n\n So, if you're on a lucky streak, you might find that Bet365 restricts the size of the bets you can place to avoid significant losses for the company. Similarly, if Bet365 suspects you are a professional gambler, they may restrict your account for the same reason.