Instead, it provides a local IMAP bridge that runs on your computer, which local desktop clients (like Thunderbird or Apple Mail) can connect to.
Marco processes your email on its secure backend and therefore cannot connect to IMAP servers running locally on your personal device.
This limitation applies to:
Proton Mail
Tutanota
HEY
Any email provider requiring a local bridge rather than a public IMAP endpoint
As soon as Proton or others offer public IMAP access, Marco will support them.