I have this exact issue as well. We have just today changed our site to use this https://github.com/Kicksend/mailcheck https://github.com/Kicksend/mailcheck ,

I have this exact issue as well. We have just today changed our site to use this https://github.com/Kicksend/mailcheck https://github.com/Kicksend/mailcheck , It will be interesting to see how well it works.