The optimal time can depend on your target audience, but generally, the following times have shown promising results:
Morning (8 AM - 10 AM): People often check their emails first thing in the morning. Late Morning (10 AM - 12 PM): This is another good slot as people might be taking short breaks. Afternoon (1 PM - 3 PM): Post-lunch hours can also be effective since people catch up on emails after their break.