News We Recently Launched SysTools Email Decryptor , SysTools Data Recovery Toolkit , SysTools Video Converter , SysTools Email Address Checker , SysTools MBOX Splitter , SysTools MBOX Merge , SysTools CSV Split & Merge , SysTools Excel Split & Merge | News SysTools Commitment to Child Safety: Upholding the Fight Against CSAM |
News We Recently Launched SysTools Email Decryptor , SysTools Data Recovery Toolkit , SysTools Video Converter , SysTools Email Address Checker , SysTools MBOX Splitter , SysTools MBOX Merge , SysTools CSV Split & Merge , SysTools Excel Split & Merge | News SysTools Commitment to Child Safety: Upholding the Fight Against CSAM |
Home » Updates » IMAP » Why IMAP Authentication Failed? & How to Fix It?

Why IMAP Authentication Failed? & How to Fix It?

  Mohit Kumar Jha
Written By Mohit Kumar Jha
Anuraag Singh
Approved By Anuraag Singh
Modified On August 25th, 2025
Reading Time 6 Min Read

Some users may face the problem of IMAP authentication failing. Why does this issue occur, and how can it be solved? All will be explained in this article. Also, I will discuss how you can secure your IMAP account so that this problem does not happen again.

Table of Contents
    1. Reasons Why IMAP Authentication Failed?
    2. How to Fix IMAP Authentication Failed? Step-By-Step
    3. Popular IMAP Accounts Errors and Solutions
    4. Steps to Avoid IMAP Failed Authentication Errors in Future
    5. Why Backup Microsoft 365 Data?
    6. To be Concluded

Here, Many users use IMAP (Internet Message Access Protocol) to access their emails from multiple email clients. It provides you a real-time synchronization across the devices. So, if you take an action on one device, it automatically reflects in other places. However, some users may encounter issues like IMAP Authentication Failed. An error where your email client is trying to connect, but the server cannot verify your login details, and you are unable to log in to the account. The reason this issue occurs is due to several factors, which I have explained below.

Reasons Why IMAP Authentication Failed?

  • The common reason for this problem is that you have entered the wrong username or password. Even a minor typo can cause this problem. So, check your details before signing in.
  • If your account has enabled 2FA, the normal password may not work; you have to enter the app-specific password that you have generated when you turn on the Two Factor Authentication option.
  • If the IMAP access is disabled from the source account. Then, you are able to log in to the IMAP account. So, enable it from the account settings.
  • Older email applications like Gmail, Yahoo, Outlook, etc. have to turn on the Less Secure Apps to connect to the IMAP. Hence, if you are using the old version, then you have to enable it.
  • Recently, the email password was changed, but it has not been updated in the email client. Also, in corporate accounts, expired passwords are common to trigger IMAP authentication errors.
  • You have entered an incorrect server name, port number, or encryption type during the manual configuration.

Therefore, there are multiple reasons for this problem. So, to resolve the problem I have a step-by-step process to fix the authentication issue.

How to Fix IMAP Authentication Failed? Step-By-Step

  1. Step 1: Confirm Email Address and Password – First of all, double-check your email address and retype your password.
  2. Step 2: Ensure IMAP/SMTP Server Settings – Check if the IMAP details are correct or not. Below are the official settings.
    • Gmail: imap.gmail.com, Port: 993 (SSL).
    • Outlook/Office 365: outlook.office365.com, Port:993 (SSL)
    • Yahoo: imap.mail.yahoo.com, Port: 993 (SSL)
    • iCloud: imap.mail.me.com, Port: 993 (SSL)
  3. Step 3: Enable IMAP Option – Make sure you enable the IMAP settings before configuring your account. Below are the steps to enable IMAP from a different email client.
    • Gmail: Settings >> Forwarding and POP/IMAP >> Enable IMAP.
    • Yahoo: By default, IMAP is already enabled. Check your account security for the restrictions.
    • iCloud/Apple Mail: Go to Mail settings and then turn on IMAP.
  4. Step 4: Use Two Factor Authentication: If you enabled 2FA, then you have to generate an app password from your provider’s security settings. Enter this password at the time of sign-in.
  5. Step 5: Update Your Email Client: Make sure that your email client is up-to-date to the latest version. Also, some old clients still use basic Authentication, which Google or Microsoft no longer supports. Switch to the application that supports OAuth2.

The above process helps you to solve the problem of all IMAP-enabled accounts. IF you are using Gmail and Outlook, then I have a specific solution that you can follow.

  1. Gmail: In the past, Gmail used the Allow less secure apps settings to let third-party apps connect with IMAP. However, in May 2022, Google removed this option for security reasons. So, if your older clients do not support OAuth2 can no longer connect their IMAP account. So, update your email client to a modern version that supports OAuth2.
  2. Outlook: Microsoft no longer supports Basic Authentication for IMAP, so you have to use OAuth2 modern authentication. To do this,
    • In your email client, click on Add Account and enter your IMAP email address.
    • On the Microsoft login page, provide your email and password. If MFA is enabled, use the authentication tool to verify your account.
    • Receive the OAuth2 token and keep it.

After resolving the IMAP authentication failed problem. Now, it is time to take steps so that the authentication problem does not happen again.

Steps to Avoid IMAP Failed Authentication Errors in Future

It is very important to take precautionary measures. IMAP authentication issues are a very common issue. Here are the steps.

  • Keep your email clients updated. IMAP-enabled email providers should be updated regularly so that it will be easy for you to log in to your account using modern authentication.
  • Make sure to enable 2FA and use app passwords when your email application does not support OAuth2. It also helps in securing your account.
  • Check your Account security settings to make sure it is not blocking your IMAP access and that modern authentication is active.
  • Review your login details so that you can avoid any IMAP login failure.

Along with these, it is also crucial to backup your IMAP email account to secure your data from any issues.

Why Backup Microsoft 365 Data?

When your IMAP authentication fails, you not only log in to your account but are also unable to access your data when you need it urgently. So, in that case, a backup file of the IMAP account can help you. SysTools IMAP Backup Tool will be very helpful in this scenario. You can easily save your entire IMAP mailbox in just a few minutes. It allows you to save any IMAP-connected account, including Outlook, Gmail, Thunderbird, and other email clients and programs. You can also use this as a preventive measure after you resolve the authentication issues.

Download Now Purchase Now

TO be Concluded

Anyone may face the IMAP authentication failed problem. Whether it is because of the incorrect login details, or using the outdated version of your email client. So, I have provided you with various ways to fix the issue. Follow them properly, and you can easily resolve it. Furthermore, I also discuss some preventive ways to avoid failed authentication in the future.

  author

By Mohit Kumar Jha

Mohit is a Microsoft Certified expert for all things Microsoft. He brings a unique perspective gained from nearly a decade of active participation in various IT forums, blogs, and social media. Known in admin circles as the go-to guru for solving user queries in the domain of cloud migration, data backup, and digital forensics. The secret to his core expertise lies in solving problems practically. Through this hands-on experience, he has acquired knowledge in diverse domains like Microsoft 365 Cloud, On-Premise Exchange Server, AD, and Entra ID.