Twitter account is suspended - What to do ? How to unsuspend it ?

When I log into my Twitter account and try to create a tweet or change settings, I see notification
"Your account is suspended and is not permitted to perform this action".

I don't think I did something wrong. I just didn't log in for a couple of months. What should I do ? How can I unsuspend my account ?

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.