Have you ever seen people incorrectly setup their email program to use POP when they should have used IMAP? We have a new feature to help protect from that scenario.
Many email clients (Outlook for example), default their internet mail connection type to POP. If you are a FastMail user, you would typically want to connect using the IMAP protocol. IMAP keeps all your email stored at the server. This allows FastMail to backup all your email folders regularly. It also provides the ability to synchronize multiple computers (or devices) to the same account and they see the same email data.
Unfortunately, some users will skip through the setup screens on their email client too quickly. The result, they've setup a POP connection. Depending upon how they setup their client, it may download all their email from FastMail and remove it from our servers.
To Disable POP access:
Login to your account on the FastMail website. Go to the Options -> Account Preferences page. At the bottom of the page, there will be a section for Access. Simply check the box next to a protocol you want to disable.
If you have disabled POP access for an account, any attempt by an email client to access via POP will fail.