Sudden increase in spam report from Yahoo

Question

Recently we experienced a sudden increase in spam reports, and all of them come from Yahoo email addresses. We see lots of registration confirmation email got marked as spam. We also saw people marking mails as spam and then opened it and clicked on the confirmation link.

We send around 150 registration emails a day, and currently sees 2 spam reports from these per day. Previously spam reports once come once a month.

We use Sendgrid to send emails.

What are the possible reason for this, and what can be done to remedy it?

Answer 1

Set up an effective SPF (TXT) record and sign your outgoing email with a DKIM signature (all of which can be done from within Sendgrid).

If the spam reports always come from Yahoo! email addresses, then something in your mail setup is not liked by Yahoo! in particular - and this is going to be difficult to help with without knowing the copy and content of the emails you send out.

I'd consider running your email addresses through a blacklist checker as well just to be sure that this isn't an issue as well.

Answer 2

It seems that Yahoo's new ajax app somehow indirectly caused this.

If the user opens an email which is automatically placed in the spam folder, and double-click on the "not spam" button, it would send two ajax requests. The first request unmarks it as spam, the second one marks it as proper spam, and results in a spam report to SendGrid.

A few people have the habit of double clicking, therefore creating false positives as they do a "not spam".