To get your IP address delisted from blacklists, you'll need to follow these instructions.
Identify the blacklists: Determine which blacklists have listed your server's IP address.
Common reasons for blacklisting include sending spam emails, hosting malware, or participating in DDoS attacks.
Some blacklists provide information on why an IP was listed. You should request its delisting from the RBL (Barracuda Central Reputation System)
system of the organization which has added it to their blacklist.
On the other hand, if you find this is a shared IP of one of the intoHOST servers, you don’t have to take any actions as we would have been already informed about this issue and taken all necessary actions to remove it from the list.
It might take around 24-48 hours for the removal to be confirmed and you will be able to send your mail without problems.