Sometimes it can happen that account on Twitter gets suspended or locked, because of several reasons. It can easily happen in case of new accounts. To unsuspend or unlock your Twitter account, you have to log in and fill this form: https://help.twitter.com/forms/general
You have to explain the problem and describe why you do not believe your account violated rules. It is recommended to ask what you have to do unsuspend the account. It could take a couple of hours or days to get a response.