Update: The system is back to normal.
We apologize for the inconvenience. I would like to apologize to anyone who is experiencing problems using our service. Unfortunately, the upgrade to our service was at the same time our provider decided to update the object storage that we use to store your encrypted attachments. When someone sends you an attachment, it takes a very long time to save the file. While the system is trying to retrieve it, your email interface gets frozen by that delay. We are working with our provider to troubleshoot this problem, and appreciate your patience.