Love This Ap – myMail box: email client app Review

I was so excited about this Ap. I use it for exclusive emails only keeping friends and business separate. But after about 3 months of using it I am getting several of my emails kicked back as Undeliverable. This is frustrating. We are in the process of troubleshooting the problem. It seems to be only one address that has the problem. ??????
Review by Tfairy1052 on myMail box: email client app.