IP Warmup

It all comes back to the reputation of your sender and IP Warmup is another practice that allows you to build it up, this time by sending a progressively increasing number of email messages from the same IP address. This process is indeed similar to a warmup and it has the purpose of strenghtening your IP reputation and implicitly the one of your sender. The Warmup Period might take you up to a month or even more in order to reach a normal sending volume on a brand new IP Address, but it would also save you the husle of getting blocked.
Email Deliverability