Email client errors: fix authentication failed, certificate warnings and sending problems

Almost every error in an email app comes down to one of three things: the server rejects your username or password, your settings point to a server name or port other than ljpc.email, or something on your device or network sits between you and the mail server. So start with one check: sign in to webmail. If that works, your mailbox and password are fine and the fix is in your email app's settings. Below you can look up your error message and see what to do.

Start here: test your password in webmail

1. Go to ljpc.email and sign in with your full email address and the password of that address.
2. Signed in? Then your address and password are correct and the mail server is working. The problem is in your email app: check the settings below.
3. Not signed in? Set a new password in the customer portal as described in set up your email on your phone, tablet and computer, then enter it on all your devices.
4. Webmail does not load at all on this network, but it does when you turn off Wi-Fi on your phone and use mobile data? Then your network's IP address has most likely been blocked for a while. See No connection to the server below.

Everything else you can do in webmail is covered in LJPc webmail.

The correct email settings

Most errors disappear once these values are right. They are the same for every domain hosted with LJPc.

If your email app fills in something else, such as mail.yourdomain.com, an IP address or port 25, replace it with the values in this table. Always choose SSL/TLS as the encryption, or STARTTLS on port 587, so your password travels to the server encrypted. We recommend IMAP, so you see the same messages and folders on every device.

Look up your error message

The exact wording differs per app and language. Find the message in the first column that looks most like yours. The sections below the table explain the steps for each type of error.

Authentication failed: your username or password is rejected

This is one of the errors we see most. Your app reaches the mail server, but the username and password do not match. If you can sign in to webmail, the cause is in what your app sends:

• The username is incomplete. Always use your full email address, so info@yourdomain.com rather than info on its own.
• The outgoing server still has an old password. Many apps store the password for incoming and outgoing mail separately. Changed your password? Enter it in both places.
• There is a typo. Watch out for capitals and for a trailing space when you copy and paste the password.
• Your app talks to a different server. If it still uses your previous provider's server or mail.yourdomain.com, you are signing in to a server that does not know your password. Enter ljpc.email.
• The authentication method does not match. Our server expects the password itself, sent over an encrypted connection. In Thunderbird choose Normal password as the authentication method, and in classic Outlook leave Require logon using Secure Password Authentication (SPA) unticked.

Cannot sign in to webmail either? Set a new password in the customer portal. Recently moved your email to LJPc? Then your address comes with a new server and sometimes a new password. Update both, or remove the account and add it again. How an email move works is explained in how to migrate email to a new server.

Do not let a device with a wrong password keep trying. After many failed attempts our mail server blocks your network's IP address for a while, and then email stops working on that network for your other devices as well.

Certificate warnings: never install a certificate

Our mail server ljpc.email has a valid Let's Encrypt certificate that every computer, phone and tablet trusts automatically. You never need to install or accept a certificate yourself. If you still get a certificate warning, one of these three things is going on:

1. The server name is not ljpc.email. A certificate belongs to a name. If your settings say mail.yourdomain.com, an IP address or your previous provider's server, that name does not match the certificate and your app rightly warns you. Set ljpc.email for both the incoming and outgoing server and the warning goes away. This is the cause we see most, especially on phones that fill in the server name themselves.
2. Antivirus or security software sits in between. Some antivirus programs inspect encrypted email by placing their own certificate between you and the server. Open the certificate details in the warning: if the issuer shows the name of your antivirus software instead of Let's Encrypt, that is where the warning comes from. Turn off scanning of encrypted email connections in your antivirus, update it, or ask its helpdesk. Incoming email is already scanned by our spam and virus filter. If you see an issuer you do not recognise and you have no antivirus installed, have your computer checked for malware.
3. The date or time on your device is wrong. A certificate is valid between two dates. If your device's clock is far off, a valid certificate looks expired. Set the date and time to automatic.

Do not accept the certificate and do not add an exception, such as Confirm Security Exception in Thunderbird. That would send your password to a server whose identity has not been verified. If your app asks again with every message whether you trust the certificate, that is a sign the server name is wrong. More about certificates in SSL certificate: what it is.

No connection to the server

If your app cannot reach the server at all, the exact error tells you where to look:

• Server not found. The name does not exist. Check for typos and enter ljpc.email. With LJPc hosting, a name like mail.yourdomain.com is not the address of your mailbox.
• Connection refused. If webmail does not load on this network either, but does over mobile data, our mail server has blocked your network's IP address after too many failed sign-ins. After wrong passwords the block lasts 30 minutes and lifts by itself. If a device tried several different or non-existent addresses, it lasts 7 days. First find the device with the old password or the removed address and fix it. If you do not want to wait, we lift the block for you. How this works is explained in what is Fail2ban.
• Timed out or interrupted. Usually port and encryption do not match: ports 993 and 465 use SSL/TLS, port 587 uses STARTTLS. If that is set correctly, your network may block the port, for example a guest network, a company firewall or a VPN. Try another network or, for outgoing mail, the other port.

Email will not send or stays in the Outbox

If incoming email works but a message stays in your Outbox, go through these steps:

1. Check the outgoing server: ljpc.email with port 465 and SSL/TLS, or port 587 with STARTTLS. Port 25 is meant for traffic between mail servers and many internet providers block it.
2. Turn on authentication for the outgoing server, with your full email address and the same password as for incoming mail. Most apps have this option in the outgoing server settings.
3. Check the size. A message can be up to 50 MB including attachments, and an attachment grows by about a third on the way. Remove a large attachment from the message in your Outbox and send a download link instead.
4. Sent a lot of email in a short time, or received our Email rate exceeded notice? Read email sending limit.
5. In classic Outlook, check whether Work Offline is on in the Send/Receive tab and turn it off.

For more causes, such as email landing in the recipient's spam folder or a domain whose DNS is hosted elsewhere, see how to fix email problems.

New Outlook fills in the servers itself

The new Outlook for Windows, Outlook for Mac and the Outlook mobile app let a Microsoft service decide which servers belong to your email address. That guess is not always right: sometimes it picks a different outgoing server or port 25, so receiving works but sending fails. Here is how to fix it:

1. When Outlook asks for the account type, choose IMAP and check the servers before you continue: incoming ljpc.email on port 993, outgoing ljpc.email on port 465, both SSL/TLS.
2. Already added the account and sending fails? Remove it and add it again with these settings.
3. If classic Outlook cannot find the settings, choose Advanced options under Add Account and tick Let me set up my account manually.

The steps for every version are in how to set up an email account in Outlook, which also explains that an IMAP account in Outlook for Mac and the Outlook app runs through Microsoft's cloud. If new Outlook still will not cooperate, classic Outlook, Thunderbird, Apple Mail and webmail all work with the same settings.

Setup guides per email app

The steps for each app, often including that app's own error messages, are in these guides:

On iPhone and iPad, our signed email profile is the quickest route: remove the account that shows the error and install the profile from set up your email on your phone, tablet and computer. All servers are then set correctly in one go.

What LJPc hosting takes care of

With LJPc hosting every domain uses the same server name, ljpc.email, with a valid certificate that every device trusts automatically. If your domain uses our nameservers, the details for automatic setup are usually in place, so many email apps find the servers themselves. And if you are stuck, we can see in our mail server logs whether and why a sign-in was rejected.

Open a support ticket, call +31 85 130 6429 or email support@ljpc.nl, and include:

• a screenshot or the exact text of the error;
• a screenshot of your server settings, without your password;
• the email address and the app you use;
• roughly when it started.

If your email is stuck, do not email us from that address; use the customer portal or call us instead. Together we get your email working on all your devices again.