IMAP Login Failed: Easily fix the Connection to IMAP Server Failed Error

Your IMAP login failed? Don’t worry, there are 5 common reasons why the connection to your IMAP server failed. In this article, we’ll show you how to fix common IMAP connection errors in a few minutes!

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IMAP Login Failed: Easily fix the Connection to IMAP Server Failed Error

Overview: How to Fix Errors if the IMAP Login Failed

There are many reasons why the connection to your IMAP server failed. Usually, the reasons are easy to track and the connection problem fixed in a few minutes – if you know what you’re looking for. Therefore, we’ve collected the top 5 common errors why an IMAP login failed, sorted by frequency:

IMAP Login Failed:
Wrong Username or Password

The most common reason why the connection to your IMAP server failed: A wrong username was provided or the password is incorrect and / or changed.

How to resolve the problem:

1. Verify the username for your mailbox:

Is the username your email address or something else? If in doubt, ask your email provider!

2. Did you misspell your password?

Make sure that you did not accidentally add a space or another character to the password. (This happens frequently when adding the password via copy and paste). Also make sure not to mix up characters when typing your password (common confusions: capital i and small caps L, zero and capital o…)

3. Did your password change?

Is it possible that your password changed or you noted down the wrong password by accident? In this case, try to reset your password. Afterwards, try to establish the IMAP connection by utilizing the new password.

Connection to IMAP Server Failed:
Wrong Mail Server Name

You are sure that your username and password are correct, but the IMAP login still failed? In this case, it’s very likely that the mail server name is incorrect.

How to resolve the issue:

1. Make sure that you entered the mail server name in the right format:

The mail server address is always written in the format subdomain.domain.tld (e.g.

Wrong formats:

2. Ask your provider for the correct mail server address

If you are unsure which mail server address to use, ask your email provider and request the address of your IMAP mail server.

3. Use the IP address of your mail server instead

Instead of the mail server name, it is also possible to connect with your mailbox by using the IP address of your mail server. For this, check the IP address of your server and enter the address instead of the server / mail server name.

IMAP Login Failed:
DNS Settings Changed after Email Migration

In most cases, this happens when migrating your emails to another provider. After the email migration, you usually change the DNS settings of your domain in order to activate your new email address. After changing the domain’s DNS settings, existing connections in your email client (e.g. Outlook, Thunderbird, Apple Mail) or any other software (e.g. email migration tools like MailJerry) fail.

How to fix the issue:

1. Use an alternative mail server name

Add an alternative mail server name or the IP address of the old mail server instead of the current mail server name in the email client / software which is reporting that the connection to the IMAP server failed.

2. Update your email credentials

After successfully migrating your emails to another provider (e.g. by using MailJerry), there is usually no need to use the old email accounts anymore. Therefore, simply update the credentials in your email client to match the settings of your new email provider.

3. Update MailJerry / your email migration tool

After the DNS settings changed, email migration tools like MailJerry will report that the IMAP login failed. To continue using functionality like the email sync, delete the existing migration and create a new one with the new settings. (And don’t worry about data chaos by running the same migration again, only data that is not already contained in your new mailbox will be transferred.)

Connection to IMAP Server Failed:
OAuth2 required

Many large providers like Office 365, Gmail or Yahoo use OAuth2, an authentication method, by default. If OAuth2 is enabled for your account, you cannot establish an IMAP connection by using your username and password, therefore, your IMAP login fails.

How to fix the problem:

1. Disable OAuth2

In the settings panel of your email provider, deactivate OAuth for your mailbox.

2. Use an app password

If you cannot disable OAuth2 for your mailbox, many providers allow you to generate an app password in the settings panel. Use this app password instead of your IMAP password to connect with your email account.

Further resources:

IMAP Login Failed:
IP Address was Blocked

Sometimes, all your credentials are correct, OAuth2 is disabled, but still the connection to the IMAP server failed. If this is the case, your IP address was usually blocked by the mail server or too many connections were established.

How to resolve the failed IMAP login:

1. Wait until your IP was unlocked

If you entered a wrong username and / or password too often, many mail servers block your IP address for security reasons. Some providers unlock your IP address after a few minutes or hours. Therefore, if possible, try again some time later.

2. Aks your provider to unlock your IP address

If you’re in a hurry or your IP does not get unlocked automatically, find your current IP address and send it to your email provider, asking them to unlock or whitelist the IP.

3. Check if someone in your company / network uses wrong credentials

If your IP gets blocked time and time again, it’s likely that someone in your company or network tries to connect with your mail server using the wrong credentials. This problem also occurs if you use the same email address on multiple devices and one device is wrongly configured.

To find out which device / user uses the wrong credentials, ask if someone in your company / network has problems receiving or sending emails.

ℹ️ If the IP address gets blocked, all users using the same IP address to connect with the same mail server are unable to connect, no matter which email address they are using.

➡️ If necessary, turn off all PCs / devices using an email address on the mail server you try to connect with. Turn them on one after the other to find out which device fails to connect with the mail server. Now fix the credentials for this device to prevent further IP blocking.

4. Too many simultaneous connections

Running many email migrations or backups of your mailbox simultaneously causes a lot of stress on your mail server. Therefore, if too many simultaneous connections are established, some providers characterise this behaviour as a security attack and block your IP address.

➡️ To prevent that the connection to the IMAP server failed, ask your provider to whitelist your IP address or allow more simultaneous connections.

➡️ If this is not possible, migrate or backup your mailboxes one after another to avoid stress on your mail server.

How to Fix Problems if the IMAP Login Failed

To sum it up, you can easily resolve errors if the connection to your IMAP server failed by:

  1. checking the username & password
  2. adding the correct address of your mail server
  3. checking your DNS settings
  4. disabling OAuth2
  5. asking your provider to unlock a probably blocked IP address

    With these easily applicable solutions, you should be able to connect with your mailbox via IMAP without any problems and the error message “imap login failed” is a thing of the past. 🎉