Horde webmail error messages: complete troubleshooting guide

Horde is a comprehensive webmail application widely used by Dutch hosting providers. Besides email, Horde also offers calendar, address book, and task list features. In this guide, we cover the most common Horde error messages and how to solve them.

1. Login failed

Symptom

You see "Login failed" or "Authentication failed" when logging in.

Cause

• Wrong password or username
• Account blocked due to too many attempts
• IMAP server not available
• Session cookies blocked

Solution

1. Check your credentials - Use your full email address
2. Reset password - Via cPanel or DirectAdmin
3. Wait 15 minutes - If blocked due to too many attempts
4. Clear browser cache - Old session data can cause problems

Prevention

Use a password manager and avoid logging in from unknown networks.

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2. Session expired

Symptom

You are suddenly logged out with "Session expired" message.

Cause

• Inactive for too long
• Browser blocking cookies
• Multiple tabs open
• VPN or proxy changing IP address

Solution

1. Log in again
2. Allow cookies - In browser settings
3. Close other tabs - Work in one tab
4. Disable VPN - Temporarily to test

Prevention

Save your work regularly and stay active in the session.

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3. IMAP server connection failed

Symptom

Error "Could not connect to IMAP server" or "IMAP connection refused".

Cause

• Mail server temporarily offline
• Firewall blocking port 993 or 143
• SSL/TLS certificate problem
• DNS resolution failed

Solution

1. Wait 5 minutes - Often temporary
2. Refresh page - Ctrl+F5
3. Check server status - With your hosting provider
4. Try again later - After scheduled maintenance

Prevention

Subscribe to status updates from your hosting provider.

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4. Unable to open mailbox

Symptom

Specific folder wont open: "Unable to open mailbox" or "Folder not found".

Cause

• Folder is corrupted
• Insufficient permissions
• Folder no longer exists
• Synchronization conflict

Solution

1. Refresh folder list - Click the refresh icon
2. Restart session - Log out and back in
3. Check via cPanel - Verify folder exists
4. Recreate folder - Delete and create again

Prevention

Dont create too many subfolders and keep structure simple.

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5. Could not save draft

Symptom

When saving a draft: "Could not save draft" or "Save failed".

Cause

• Drafts folder does not exist
• Mailbox quota reached
• Connection lost
• Attachment too large

Solution

1. Check quota - Clean mailbox if full
2. Create Drafts folder - Via folder management in Horde
3. Reduce attachments - Remove large files
4. Copy text - Save draft locally as backup

Prevention

Keep mailbox under 80% full and verify Drafts folder exists.

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6. Calendar sync failed

Symptom

Calendar items dont appear or "Sync failed" for calendar.

Cause

• CalDAV server unreachable
• Wrong calendar URL
• Authentication expired
• Too many items in calendar

Solution

1. Refresh calendar - Via menu Calendar > Refresh
2. Check settings - CalDAV URL and password
3. Remove and re-add - The external calendar
4. Split large calendars - Create multiple calendars

Prevention

Dont use too many external calendars and sync regularly.

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7. Address book unavailable

Symptom

Contacts wont load or "Address book unavailable" appears.

Cause

• LDAP or CardDAV server offline
• Database connection failed
• Permissions problem
• Corrupt contacts data

Solution

1. Refresh the page
2. Switch to another address book - If you have multiple
3. Export contacts - As backup via CSV
4. Contact hosting - For database check

Prevention

Export your contacts regularly as backup.

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8. Quota exceeded

Symptom

No new emails and message "Over quota" or "Mailbox full".

Cause

• Storage limit reached
• Large attachments
• Trash not emptied
• Spam folder full

Solution

1. Delete large emails - Sort by size
2. Empty Trash - Permanently delete
3. Clear Spam - Counts toward quota
4. Archive locally - Download old mails

Prevention

Set automatic deletion for Spam and Trash folders.

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9. Authentication error when sending

Symptom

When sending: "SMTP authentication failed" or "Relay access denied".

Cause

• SMTP password incorrect
• SMTP server different from IMAP
• Security setting
• IP blocked

Solution

1. Check identity - In Horde preferences
2. Reset password - Via control panel
3. Check SMTP server - Often mail.yourdomain.com
4. Contact support - Hosting support

Prevention

Use the same credentials for IMAP and SMTP.

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10. Timeout error

Symptom

Page wont load completely with "Timeout" or "Request timed out".

Cause

• Slow server
• Loading large mailbox
• Network problems
• Server overloaded

Solution

1. Wait and try again
2. Reduce display - Fewer emails per page
3. Use filters - View only recent mail
4. Try outside peak hours

Prevention

Archive old emails and keep inbox manageable.

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General tips for Horde problems

• Update your browser - Old versions may be incompatible
• Clear cache regularly - Prevents session problems
• Check server status - Many problems are server-related
• Make backups - Export contacts and calendar regularly

Need help?

Contact your hosting provider if these solutions dont work.

Related articles

• Horde webmail guide - Complete user guide
• Horde calendar guide - Managing calendar
• Roundcube error messages - Alternative webmail
• Webmail error messages - General tips
• IMAP vs POP3: what is the difference? - Protocol explanation

Frequently Asked Questions

How long does it take to implement this?

Implementation time varies per situation. Simple configurations can be done within an hour, more complex setups may take several hours to a day.

What are the costs?

Costs depend on your hosting provider and package. Many basic features are included for free, advanced features may incur additional costs.

Do I need technical knowledge?

You need little technical knowledge for the basics. Most hosting providers offer extensive documentation and support to help you.