Set sending time optimization

Set this newsletter to optimized send time for each recipient tomorrow morning. Use recipients' past open behavior to pick the minute, but do not send before 07:00 or after 20:00 local time. If a recipient has no history, default to 09:00. Verify that the optimization window respects the local timezone and exclude recipients flagged as Do Not Disturb.

Before I enable send-time optimization, make the settings approval-ready for the marketing director: summarize which recipients will get personalized times versus the 09:00 default, show the time zone mapping rules, explain how 'no-history' addresses are handled, and flag any segments where optimization would push sends into inappropriate hours (children's products, international markets). Also surface the expected change in open rate.

I turned on send-time optimization and several subscribers in the UK are getting emails scheduled at 02:00 local. I only set the 07:00–20:00 constraint but can't see why those times were chosen. What likely explanation fits this behavior, what logs or recipient data should I check quickly, and what is the corrective step that fixes it before more sends?

We enabled personalized send times to boost opens, yet every few campaigns recipients complain about messages at late-night hours. I manage timing but not the data pipelines. Where do we lose control: poor timezone detection, stale last-open data, or failing to respect business-hour constraints? Recommend one immediate validation to stop rude-hour sends and one recurring guardrail to prevent this.