The cause of your emails being sent in the middle of the night is most likely due to a combination of your team's daily send limit and too many emails being scheduled or sent automatically from a Cadence.

If your daily send limit is set, any emails that go over that limit will be delayed for 24 hours. This means that when an email limit is reached, scheduled or automated emails will not send out at the time you originally scheduled.

Staying true to the "daily" send limit, Salesloft will place the emails on a queue for the following day. These emails will begin sending the following "day" at midnight in your timezone. If you already have scheduled emails in your queue for that day, the excess emails will send after the previously scheduled emails.  

People you are emailing that are based in different timezones will also receive emails at midnight your time. So, if you are based in California and sending to someone in Boston, they may receive the email at 3 AM.

There are a few suggestions to solve the automated email and daily send limit timing:

• If you'd like to only limit yourself to a small number of emails a day, make sure you only add that number of People a day to a Cadence.
• Have a team admin increase the daily send limit.
• In your Cadence, keep track of your daily send limit maximum and change the "due date" for any appropriate People. For example, if you have a daily send limit of 10 emails a day, you would want to change the due date for every 10th Person.