According to bianance document as belowed, the error -403 means that it will ban of our IP for 2 minutes to 3 days. But I got a -403 error for more than 3 days and is still banned.
Is it possible for you to use a different IP? If you’re using a VPS/server you could assign a new static IP and use that instead. Otherwise all you can do is wait as outlined in the support thread you linked.