We have a list of 50,000 that we send every day with site content updates, as well as marketing campaigns. We use MailChimp for most of our mailings. We've seen a sudden 30-40% drop in our open rates starting a month ago. The majority of the drop seems to be from gmail, which comprises over half of our subscribers. Since we haven't made any changes to our content or the style of our subject lines, we suspect it may be something else.

Based on several best practices articles about better deliverability, we did make several changes around the same time, but so far they seem to doing the opposite, at least circumstantially. Here's what we did:

  1. Enabled DKIM/SPF authentication for our domain
  2. Started including first and last name in the TO field, instead of just first name
  3. Started using consistent FROM names with just our business name in it.

At first I thought it was the FROM name that was losing engagement, but we went back to our old FROM names almost two weeks ago and it doesn't seem to have helped much.

Any other ideas? Thanks!