“How much email do you send? High-volume senders are always a red flag, especially when volumes are inconsistent. Do you send approximately the same number of emails each week or month, or is your mailing schedule all over the map? Consistent volumes based on subscriber preferences are a key consideration for ISPs.”
Remain consistent about the number of emails you send in a day, week, month, etc. Don’t go from sending one email a week to 10, as this will confuse consumers and likely make them place your mail in junk and spam folders.