My mail app can't connect, or keeps asking for my password

Applies to: All plans (mailboxes included with your hosting). For Professional Email (Microsoft 365 or Google Workspace), sign-in is handled by Microsoft or Google: see Email isn't sending or receiving.

When a mail app stops connecting to a mailbox that used to work, the cause is usually one of five things. Most of them are security measures that protect your mailbox, and they clear on their own or after one step from you. Find your case below.

Find your case

Nobody on your office network can connect, but webmail works on a phone using mobile data: see 1.
The correct password is refused, or the app keeps asking for it: see 2.
An error about plain-text login or an unencrypted connection: see 3.
A certificate warning for mail.yourdomain.com: see 4.
A shared mailbox works on some devices but not on others: see 5.

1. Nobody on your network can connect

What you see: mail apps on every computer and phone in the office time out or say they cannot reach the server, without any password error. Your website may show a security check page when you open it from the office. Webmail still works on a phone that uses mobile data instead of the office Wi-Fi.

Why: our firewall has temporarily blocked your network's public IP address because a security rule was triggered from it, often by a login or a form on your own website (for example several failed WordPress logins). While the block lasts, mail apps on that network cannot connect at all.

Fix:

On a computer connected to the affected network, open your website or https://node11.maxinodes.com:2096 in a browser.
If a security check page (a CAPTCHA) appears, complete it. You do not need to log in to webmail afterwards.
Wait a minute or two, then try your mail app again.

Result: the block on your network is lifted, and mail apps connect again within a minute or two.

If it keeps happening, tell us, with your network's public IP address (see the last section). We can see which rule was triggered and, for an office with a fixed IP address, help stop it happening again.

2. The right password is refused

What you see: the app keeps asking for the password, or says it is wrong, even though you are typing the correct one. Sometimes every device in the office that uses the mailbox is refused at the same time.

Why: after 10 wrong password attempts within 5 minutes, sign-in to that mailbox is locked for 5 minutes, and during that time even the correct password is refused. The usual cause is an old phone, tablet or laptop that still has an old password saved and keeps retrying it in the background.

Fix:

Update the saved password on every device that uses the mailbox: phones, tablets, laptops, and each Outlook profile. Remove the account from any device you no longer use.
Check that the username is the full email address (for example anna@yourdomain.com), not just the part before the @ and not your cPanel username.
Wait 5 minutes without trying, then sign in once.

If you are not sure of the password, set a new one in your client area (your hosting service -> Email Accounts) or in cPanel under Email -> Email Accounts, then update it on every device.

Using a VPN? Some VPN services and shared network addresses are on lists of known password-guessing sources, and sign-ins from them are refused. Switch the VPN off, or try another network.

3. The app says plain-text login is not allowed

What you see: an error such as "Plaintext authentication disallowed" or "the server does not support plain-text logins", usually on port 143 or 110.

Why: we only accept sign-ins over an encrypted connection, so unencrypted logins on ports 143 (IMAP) and 110 (POP3) are refused.

Fix: in the account's server settings, use IMAP on port 993 or POP3 on port 995 with SSL/TLS, and for sending, SMTP on port 465 (SSL/TLS) or 587 (STARTTLS), with authentication switched on. If your app only offers 143 or 110, choose STARTTLS. Do not use port 25 for sending from a mail app: many networks block it. The full settings are in Mail app settings.

4. A certificate warning for mail.yourdomain.com

What you see: the app warns that the server's certificate is not valid, is not trusted, or does not match mail.yourdomain.com. This usually happens soon after the domain was set up with us or moved to us.

Why: the free certificate for mail.yourdomain.com is issued automatically, but only once your domain points at us, so there is a gap before it is in place.

Fix: do not accept the warning or mark the certificate as trusted. Use node11.maxinodes.com as the incoming and outgoing server name instead: it has a valid certificate from the start and reaches the same mailbox. Once the certificate for mail.yourdomain.com is in place, you can switch back. If the app cannot find mail.yourdomain.com at all, its DNS record is missing: see The DNS records your email needs, and use node11.maxinodes.com in the meantime.

5. Some devices connect, others are refused

What you see: a shared mailbox (such as info@) works on some computers and phones in the office but not on others at the same time, with an error such as "Maximum number of connections from user+IP exceeded".

Why: one mailbox can have up to 20 IMAP connections (or 3 POP3 connections) open at once from the same network address. Each mail app opens several IMAP connections, so a shared mailbox open on many devices in one office can reach the limit.

Fix: close the mailbox on devices that do not need it, lower the number of connections in the app's advanced settings if it has that option, or give people their own mailboxes and send the shared address to them with a forwarder. For POP3, make devices check for mail less often, or switch them to IMAP.

If that did not work

your network's public IP address: on a device connected to the affected network, open a "what is my IP" website and copy the address it shows;
the mailbox address;
the time the problem happened, with your time zone;
the mail app and device, and the exact error message (a screenshot helps);
whether webmail works on a phone using mobile data.

On a Managed plan we can reset the mailbox password and set up your mail app with you. See What our support covers (Self-Managed vs Managed) and What to include when you contact support.