How to Connect Mailbux to Any Email Client (Universal IMAP/SMTP Guide)

Whether you prefer Spark, Canary Mail, FairEmail, K-9 Mail, Mailbird, Postbox, Evolution, Geary, or any other email application — your Mailbux custom domain email works with all of them. This universal guide gives you the exact server settings and step-by-step instructions to connect Mailbux to any email client on any platform.

No proprietary apps required. No ecosystem lock-in. Just standard IMAP, SMTP, and POP3 protocols that work everywhere.

Mailbux Server Settings — The Complete Reference

These are the only settings you need to connect any email client to your Mailbux account. Bookmark this page for quick reference.

Incoming Mail (IMAP — Recommended)

Setting	Value
Server	my.mailbux.com
Port	993
Security	SSL/TLS
Authentication	Normal password
Username	Your full email address (e.g., you@yourdomain.com)
Password	Your email password

Incoming Mail (POP3 — Alternative)

Setting	Value
Server	my.mailbux.com
Port	995
Security	SSL/TLS
Authentication	Normal password
Username	Your full email address
Password	Your email password

When to use POP3: Only use POP3 if you want to download emails to a single device and optionally delete them from the server. For most users, IMAP is the better choice because it keeps email synchronized across all your devices.

Outgoing Mail (SMTP)

Setting	Value
Server	my.mailbux.com
Port	587
Security	STARTTLS
Authentication	Normal password
Username	Your full email address
Password	Your email password

IMAP vs POP3: Which Should You Choose?

Use IMAP if you access email from multiple devices (phone, laptop, tablet, webmail). IMAP synchronizes everything — read/unread status, folders, drafts, sent mail — across all devices in real time.

Use POP3 only if you want to download email to one device and do not need it accessible elsewhere. POP3 downloads messages and can optionally delete them from the server, which is useful for archival purposes but not for everyday multi-device use.

For the vast majority of users, IMAP is the right choice.

Calendar and Contacts Sync (CalDAV and CardDAV)

Mailbux supports CalDAV for calendar sync and CardDAV for contacts sync. If your email client supports these protocols, you can keep your calendar events and address book in sync across all devices.

Service	URL
CalDAV (Calendar)	https://my.mailbux.com/dav
CardDAV (Contacts)	https://my.mailbux.com/dav

Use the same email address and password you use for IMAP/SMTP. Most clients that support CalDAV/CardDAV will auto-discover your calendars and address books from the base URL above.

Quick Setup Guides by Email Client

Below are client-specific tips to get you connected faster. The server settings are the same for all clients — the differences are in where you enter them.

Spark (iOS, Mac, Android, Windows)

Open Spark and tap Add Account
Choose "Other" or "IMAP"
Enter your Mailbux email address and password
If auto-detection fails, enter the IMAP and SMTP settings from the tables above
Spark will sync your inbox immediately

Spark does not support CalDAV/CardDAV natively, so calendar and contacts sync will need a separate app on your device.

Canary Mail (iOS, Mac, Android, Windows)

Open Canary Mail and go to Settings > Accounts > Add Account
Select "Other (IMAP)"
Enter your email, password, and the IMAP/SMTP server settings
Enable encryption features if desired — Canary Mail supports PGP

Canary Mail is a great option if you value privacy, as it offers built-in end-to-end encryption support.

FairEmail (Android)

Open FairEmail and tap the wizard icon
Select "Other provider"
Enter your Mailbux email and password
FairEmail will ask for incoming (IMAP) and outgoing (SMTP) server details — enter the settings from the tables above
Grant the necessary permissions and complete setup

FairEmail is open-source, privacy-focused, and one of the most feature-rich Android email clients available.

K-9 Mail / Thunderbird for Android

Open K-9 Mail and tap Add Account
Enter your Mailbux email address and password
Select IMAP as the account type
Set incoming server to my.mailbux.com, port 993, security SSL/TLS
Set outgoing server to my.mailbux.com, port 587, security STARTTLS
Complete the wizard

K-9 Mail has been adopted as the official Thunderbird mobile app for Android, so the setup process is identical for both.

Mailbird (Windows)

Open Mailbird and click Add Account
Enter your Mailbux email address — Mailbird may attempt auto-discovery
If auto-discovery fails, click "Edit server settings"
Enter the IMAP and SMTP settings from the tables above
Click Continue to complete setup

Mailbird offers a clean interface with app integrations (Slack, WhatsApp, Google Calendar) that can enhance your workflow.

Postbox (Windows, Mac)

Open Postbox and go to File > New > Existing Mail Account
Enter your name, Mailbux email address, and password
Click Manual Config if auto-detection does not find the correct settings
Set IMAP: my.mailbux.com, port 993, SSL/TLS
Set SMTP: my.mailbux.com, port 587, STARTTLS
Click Done

Postbox is designed for power users who manage multiple email accounts and need advanced organization features.

GNOME Evolution (Linux)

Open Evolution and go to Edit > Preferences > Mail Accounts > Add
Enter your name and Mailbux email address
For Receiving Email: select IMAP, server my.mailbux.com, port 993, encryption SSL/TLS
For Sending Email: select SMTP, server my.mailbux.com, port 587, encryption STARTTLS
Evolution also supports CalDAV and CardDAV — add https://my.mailbux.com/dav under Calendar and Contacts

Evolution is the most full-featured Linux email client, with integrated calendar, contacts, and task management.

Geary (Linux)

Open Geary and click Add Account
Enter your Mailbux email and password
If auto-discovery fails, enter server settings manually
IMAP: my.mailbux.com, port 993, SSL/TLS
SMTP: my.mailbux.com, port 587, STARTTLS

Geary is a lightweight, simple email client for Linux that focuses on ease of use. It is ideal if you want a clean, distraction-free email experience.

General Setup Tips (Works for Any Client)

No matter which email client you use, these tips apply universally:

Always use your full email address as the username — not just the part before the @ sign. For example, use hello@yourdomain.com, not just hello.
Use IMAP unless you have a specific reason for POP3 — IMAP keeps everything in sync across devices.
Authentication method should be "Normal password" — Mailbux uses standard password authentication over encrypted connections.
Do not use your own domain as the server name — always use my.mailbux.com as the server for both incoming and outgoing mail.
Port 465 (SMTP with SSL) is also supported as an alternative to port 587 with STARTTLS, but 587 is the recommended standard.

Troubleshooting Common Issues

"Authentication Failed" or "Login Failed"

This is the most common error. Verify that:

You are using your full email address as the username
Your password is correct (try resetting it from your Mailbux dashboard)
You are connecting to my.mailbux.com, not a different server

"Connection Timed Out" or "Cannot Connect"

Check that:

The server hostname is exactly my.mailbux.com
Ports 993 (IMAP), 587 (SMTP), or 995 (POP3) are not blocked by your network or firewall
You are using the correct encryption type (SSL/TLS for IMAP/POP3, STARTTLS for SMTP)
If you are on a corporate network, check with your IT department — some networks block non-standard email ports

"Certificate Error" or "Untrusted Certificate"

Mailbux uses valid SSL certificates from a trusted certificate authority. If you see this error, make sure:

The server is set to my.mailbux.com (not your own domain)
Your device's date and time are correct — expired system clocks cause certificate validation failures
Your operating system and email client are up to date

Emails Sending but Not Being Received by Others

This is usually a DNS configuration issue, not an email client problem. Log into your Mailbux dashboard and verify that your domain's MX, SPF, DKIM, and DMARC records are all set up correctly. Mailbux provides the exact DNS values you need during domain setup.

Sent Emails Not Appearing in Sent Folder

Some email clients store sent emails locally instead of on the server. Check your client's settings and make sure it is configured to save sent messages to the IMAP Sent folder rather than a local folder. This ensures sent emails are visible from webmail and other devices.

Why Standard Protocols Matter

Mailbux uses open, standard email protocols — IMAP, SMTP, POP3, CalDAV, and CardDAV. This means:

No vendor lock-in — switch email clients anytime without losing data
Works on every platform — Windows, Mac, Linux, iOS, Android, and any device with an email client
Future-proof — these protocols have been the backbone of email for decades and will continue to be supported
Your choice of client — use the app that fits your workflow, not the one your email provider forces on you

This is a deliberate design choice. Your email hosting should not dictate which software you use to read your email.

Quick Reference Card

Save these settings for easy access:

Protocol	Server	Port	Security
IMAP	my.mailbux.com	993	SSL/TLS
POP3	my.mailbux.com	995	SSL/TLS
SMTP	my.mailbux.com	587	STARTTLS
CalDAV	https://my.mailbux.com/dav
CardDAV	https://my.mailbux.com/dav

Username is always your full email address. Password is the one you set in your Mailbux dashboard.

Final Thoughts

Connecting your Mailbux email to any client should take less than five minutes. The settings are the same regardless of which application you choose — my.mailbux.com for the server, standard ports, and standard encryption. No special configuration, no proprietary protocols, no surprises.

Whether you are a Spark user on iOS, a FairEmail user on Android, a Mailbird user on Windows, or an Evolution user on Linux — Mailbux works with your preferred email client out of the box.

New to Mailbux? Create your free account — 15 GB storage, custom domain, and full IMAP/SMTP/POP3 access. Connect it to any email client you like.