This is because, as explained in this faq post which says
No. The automatic ban is at a lower level than account. If you do end up creating a new account, it will also receive the same ban.
Which means the most likely outcome was that somebody using the same IP address (possibly a family member, coworker, or schoolmate) got an answer ban, and now the IP address is answer banned.
This should be possible to fix, and here are a couple ways that might fix it
- take advice from the faq, which says
The ban also takes into account the IP address. If you browse from a shared computer, or from a location that gives the same IP address to many end users, it's enough that another user who was banned or triggers the ban may affect other users accessing from the same location.
To help rectify this, browse from a different location.
- As stated in the comments, creating an account will possibly help.
I know this was already kinda answered in the comments, but I decided to post it as an actual answer so that it can be helpful to more people in the future, and is more visible.