Some email services providers tend to have stricter spam filters than others. You can target those contacts separately with different content to ensure better deliverability. Below is an example of a segment that excludes contacts who use Gmail from the sendout.
Segment
In this example, we show the criterion in combination with other criteria, just to demonstrate it with additional context. However, to achieve the objective, we only need the last condition - Email Domain Does Not Contain: @gmail.
