Mailcow + Thunderbird Setup Guide (Email + Calendar)

Mailcow + Thunderbird Setup Guide (Email + Calendar)

This guide shows staff how to properly connect Thunderbird to Mailcow for:

• Email (IMAP + SMTP)
• Calendar (CalDAV via SOGo)

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1. Create an App Password in Mailcow

1. Log in to your Mailcow webmail account.
2. Open the Mailbox menu.
3. Select App Passwords.
4. Click Create app password.
5. Name it something like: Thunderbird.
6. Choose allowed protocols:
   • IMAP
   • SMTP
   • DAV (for calendar)
7. Copy the generated password.

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2. Configure Email in Thunderbird

1. Open Thunderbird.
2. Go to Account Settings → Add Mail Account.
3. Enter:
   • Your full email address
   • Any name you prefer
   • App Password from Mailcow (NOT your main password)
4. Thunderbird should auto-detect settings.

Required Server Settings

Setting	Value
Incoming (IMAP) – Host	Your Mailcow server domain
Incoming (IMAP) – Port	993
Incoming (IMAP) – SSL	SSL/TLS
Incoming (IMAP) – Authentication	Normal Password
Outgoing (SMTP) – Host	Your Mailcow server domain
Outgoing (SMTP) – Port	465 (or 587 if needed)
Outgoing (SMTP) – SSL	SSL/TLS
Outgoing (SMTP) – Authentication	Normal Password

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3. Enable CalDAV Calendar in Thunderbird

Mailcow uses SOGo for calendar sync.

1. In Thunderbird, go to Calendar.
2. Click + New Calendar.
3. Choose On the Network.
4. Select CalDAV.
5. Enter your calendar URL (example format):

https://your-mailcow-server/SOGo/dav/your-email/Calendar/personal/

1. When prompted:
   • Username: Your full email address
   • Password: Your App Password
2. Complete setup.

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4. Common Issues to Avoid

• Using your main password instead of an App Password → causes "wrong credentials."
• Forgetting that the calendar URL must end with a trailing slash /.
• Choosing the wrong authentication type (must be Normal Password).
• Having saved old passwords in Thunderbird. Clear them here:
  • Settings → Privacy & Security → Saved Passwords → Remove old entries.

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5. Verification Checklist

• Email works for sending and receiving.
• Calendar events appear in Thunderbird.
• Your App Password is active in the Mailcow App Passwords list.

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If these steps are followed, Thunderbird will reliably sync both email and calendar with Mailcow.