Setting up mail in your mail client

Once you’ve created a mailbox in Plesk, you’ll typically want to set it up in your mail client — Apple Mail, Outlook, Thunderbird on the desktop, or the respective smartphone app. Here are the server details and setup guides per platform.

Server details — the basics

Setting	Value
IMAP server	mail.deinedomain.de
IMAP port	993
IMAP security	SSL/TLS
SMTP server	mail.deinedomain.de
SMTP port	465 (SSL/TLS) or 587 (STARTTLS)
Authentication	”Same as incoming server” or username + password separately
Username	the full mail address (info@deinedomain.de)
Password	the mailbox password, not the Plesk password

Some mail clients ask for the username as the mail address, others want only the local part — Plesk accepts both variants.

Apple Mail (macOS)

1. Mail → Settings → Accounts → +
2. Choose Other Mail Account
3. Enter name (display name), mail address, password
4. Click Configure manually (auto-discovery sometimes doesn’t find it)
5. Enter the mail server details from above
6. Sign in → the mailbox connects

Apple Mail tests the connection during setup. If it errors: double-check the server details, especially the TLS/SSL checkboxes.

Apple Mail (iPhone / iPad)

1. Settings → Mail → Accounts → Add Account
2. Choose Other
3. Add Mail Account
4. Fill in the fields (name, mail address, password, description)
5. Next → iOS tests — if auto-discovery works, done
6. If not: fill the fields manually:
   • IMAP: hostname mail.deinedomain.de, username, password
   • SMTP: same hostname, username, password

Outlook (Windows / Mac)

1. File → Add Account (Outlook 2016+)
2. Mail address → Connect
3. Outlook asks for the account type → IMAP
4. Server details:
   • Incoming server: mail.deinedomain.de, port 993, SSL
   • Outgoing server: mail.deinedomain.de, port 465, SSL
5. Password → Connect

Outlook sometimes makes odd auto-discovery attempts that fail. If that happens: advanced setup and enter it manually.

Thunderbird

1. File → New → Existing Mail Account
2. Enter name, mail address, password
3. Continue — Thunderbird tries auto-discovery
4. If not: Manual configuration:
   • IMAP: mail.deinedomain.de, port 993, SSL/TLS
   • SMTP: mail.deinedomain.de, port 465, SSL/TLS
   • Authentication: normal password
5. Done

Thunderbird is usually very robust with auto-setup.

K-9 Mail (Android, free)

1. + new account
2. Mail address, password
3. Configure manually
4. Account type: IMAP
5. Server details as above
6. Done

Gmail app (iOS / Android)

The Gmail app supports IMAP accounts:

1. + Add account → Other
2. Mail address, password
3. Server details manually

Apple Mail and Spark (iOS / Android)

Spark supports IMAP — setup is analogous to Apple Mail, with extra features (snooze, templates).

Pitfalls

Login fails despite the correct password

• Username: the full mail address, not just the local part
• Password: no leading/trailing spaces
• Plesk password vs. mailbox password: two different things

”Connection not secure” / certificate warning

The mail client doesn’t accept the SSL certificate. Possible reasons:

• you’re using mail.altedomain.de but the cert is for mail.deinedomain.de
• the cert has expired — that should never happen with us, otherwise open a ticket

Fix: set the server address to the correct hostname.

SMTP doesn’t work (“mail cannot be sent”)

• enable SMTP authentication (“same as incoming server”)
• port 465 (SSL) or 587 (STARTTLS) — not 25 (that’s server-to-server mail)
• some ISPs block outgoing port 25 — not relevant for our setup, but good to know

Mail only comes in, not out (or the other way around)

Check both the IMAP and SMTP settings — one of them often gets forgotten.

The mail client loads very slowly the first time

The initial sync of lots of mail takes a while. With big mailboxes (>10 GB): hours are possible.

Push vs. polling

• iPhone Apple Mail: uses IMAP IDLE (push) — new mail arrives instantly
• Android K-9: similar, IDLE support
• Outlook desktop: polls every 1-15 minutes (default)
• Gmail app: polls

For instant notifications: use an IMAP IDLE-capable client and enable “push” in its settings.

Multiple devices at once

As many as you like. iPhone + Mac + Outlook on the office PC + webmail — all in parallel.

IMAP syncs all actions (read status, folder moves) between all clients.

Always-online mode vs. offline caching

• Online mode: the mail client fetches mail on demand, small local footprint
• Offline cache: mail stored locally, readable without internet

Default behavior depends on the client. On mobile devices: a 30-day cache is typical.

Frequently asked questions

Which SMTP port — 465 or 587? Both work with us. 465 (SSL/TLS) is more robust, 587 (STARTTLS) is the historical “mail submission” standard.

What if the mail client automatically suggests port 25? Port 25 is server-to-server mail, not client-to-server. Change it to 465 or 587.

Do I need separate app passwords for mobile? No, Plesk mail has no mandatory 2FA. The mailbox password works directly.

How many mails can I send per day? Standard: ~500 mails/hour per mailbox. For commercial newsletters (>1000 mails), use a dedicated sending platform.

My mail client shows an address book — can I sync it via Plesk? Plesk mail has no CardDAV server. Address books are local per mail client. For cloud sync: use Nextcloud or iCloud.

Calendar invitations — does that work with Plesk mail too? Plesk has no CalDAV/calendar. You can still receive .ics invitations and add them to your local calendar. For full calendar integration: a separate Mailcow server.

My mail client sometimes shows “disconnected” — fix? The IMAP connection can drop briefly on timeouts. Modern clients reconnect automatically. If it keeps happening: check your internet connection.

How do I use PGP / S/MIME? Nothing changes on the mail side — encryption happens in the client. Setup per client (Mail, Thunderbird with Enigmail, etc.).

What’s next

• Creating a mailbox
• Webmail with Roundcube
• Mail aliases, forwarding, auto-responders