Proton Mail

Proton Mail is end-to-end encrypted and does not expose a public SMTP server in the usual way. Instead, you run a small companion app called Proton Mail Bridge on your computer. The Bridge exposes a local SMTP endpoint on 127.0.0.1; you point Xenocept at that local endpoint, and the Bridge handles encryption and submission to Proton’s servers.

This means: the Bridge must be running on the same machine as Xenocept any time you want the Email destination to work.

1. Confirm Your Account Is Eligible

Proton Mail Bridge is included with Mail Plus, Proton Unlimited, Visionary, and Mail Essentials/Professional/Enterprise plans for Proton Business. Free Proton Mail accounts cannot use the Bridge.

If you’re on a free Proton account, you’ll need to either upgrade or pick a different email provider for the Xenocept Email destination.

2. Install Proton Mail Bridge

1. Visit proton.me/mail/bridge and download the Bridge for your operating system (macOS, Windows, Linux).
2. Install it the usual way for your OS.
3. Launch Bridge and sign in with your Proton Mail credentials. If you have 2FA on your Proton account, you’ll be prompted for the second factor here as well.

The Bridge runs in the background and presents a small status icon in your menu bar / system tray. It needs to stay running for the SMTP endpoint to be reachable.

3. Find Your Local SMTP Credentials

Bridge generates a new, separate password for your local SMTP endpoint. This is not your Proton Mail account password — never use your account password with third-party clients.

1. Open the Bridge interface (click the status icon → Open Proton Mail Bridge).
2. Click on your account in the Bridge.
3. Find the Mailbox configuration or SMTP section. Bridge displays:
   • The SMTP server: 127.0.0.1
   • The SMTP port (typically 1025, but Bridge picks an available port at install time — check what yours says)
   • The Username (your Proton email address)
   • A generated SMTP password (a long random string)
4. Copy the SMTP password from the Bridge UI. You can re-display it any time from Bridge if you forget it.

4. Configure the Email Destination in Xenocept

Open the Xenocept Settings UI → Destinations → New Destination → Email. Fill in:

Save the destination and submit a test session. Bridge handles encryption and transit to Proton’s servers transparently.

Common Issues

• “Connection refused.” Bridge isn’t running, or it’s running but the port differs from what you typed. Open Bridge and confirm the port number.
• “Authentication failed.” You used your Proton account password instead of the Bridge SMTP password. They’re different by design. Copy the Bridge-generated value.
• Port already in use. If another app on your machine claims the same port (some media-streaming apps grab 1025), Bridge lets you change to a different port from its settings. Then update Xenocept to match.
• Certificate warnings. Bridge uses a self-signed certificate for the local TLS connection. Xenocept’s Email plugin should accept the Bridge’s certificate automatically; if it doesn’t, see the Proton Bridge documentation for adding the Bridge CA to your system’s trust store.

When Bridge Isn’t an Option

If you can’t run Bridge (free Proton account, restricted environment), you have a couple of workarounds:

• Use a non-Proton email account just for Xenocept. The other guides in this section cover Gmail, iCloud, Yahoo, Fastmail, and Outlook.com — any of those work as a Xenocept Email destination.
• Add a forwarding rule in Proton that drops Xenocept-tagged messages into a Proton inbox, but send them from a different provider.