What’s the difference between warning and enforcement phases?

Warning and enforcement phases represent different severity levels in compliance enforcement. During warning phases, non compliant senders experience increased filtering but not outright blocking, giving time to address issues. Enforcement phases apply full blocking to persistent violators.

Gmail's rollout began with soft enforcement in February 2024, applying warnings and temporary failures while monitoring sender responses. Senders fixing issues during this phase avoided escalation. Those ignoring warnings faced progressively stricter treatment.

The distinction matters for planning. Warning phases provide grace periods to identify and fix problems. Treating warning phase as the deadline rather than waiting for enforcement prevents the harder consequences of full blocking and reputation damage.