How to Fix Gmail IMAP Error 78754 on Outlook?

Microsoft Outlook is a part of Microsoft Office Suite which helps the user to manage his/her personal information. It is an email client for primary use but it also includes features like calendar, contact manager, task manager, etc. for the user to schedule his daily life.

The 78754 Failure is a Microsoft Outlook web log-in error experienced by an individual when the user tries to access his/her Gmail account. An IMAP glitch causes the mail server to forcibly shut out a client while it was trying to gain access to the user emails through the Microsoft Outlook platform.

This error usually pops up in cases; when the user log-in credentials are not recognized, when the user is trying to access his/her account from a new device/location, when Google detects suspicious user log-in, when an app-specific password is required for signing in, instead of the regular account password or any other similar situation. The error notification is displayed to the user as follows:

Before we proceed any further, you need to have some understanding of Internet Message Access Protocol (IMAP).

What is IMAP Server?

IMAP is a standard electronic mail protocol platform that stores messages on a mail server and then allows the user to view, manipulate and organize the emails as the user sees fit. The messages stored on the mail server are originally stored on the user’s machine.

IMAP also allows the user to access all the mainmail controls on multiple mail clients (Outlook, MailExplorer, etc.) even on different devices, synchronizing everything in real-time i.e. a user could set up his/her mail account on Microsoft Outlook desktop client as well as on Outlook Android/iPhone app at the same time.

What Causes Gmail IMAP Error 78754 on Outlook?

As already illustrated in the case situations above, this error may arise due to many reasons. Most reported ones are as follows:

Solution 1: Re-verify your Gmail Log-in Credentials

Simply just re-verify your log-in credentials so that they are correct in every way possible. If this is the error origin, then, this solution will probably work. Thus, it should be your first point of call. After confirming your log-in details, perform a log-in check on Outlook using a PC or mobile device and the error should be resolved.

Note: Since Google protected passwords are case-sensitive, make sure to check your Caps Lock key to avoid any mistakes.

Solution 2: Enabling IMAP and Allow Less Secure Apps on Gmail

As explained earlier, IMAP servers are needed to make Microsoft Outlook work properly. Hence, it is a must to enable it. In case, users have it disabled, they may face this error. You can enable it by performing the following steps:

1. Open the Gmail Log-in page from your web browser.
2. Log-in to Gmail with your account details.
3. On the top right corner, click the Gear Icon and select Settings from the drop-down menu.

   

4. Switch to Forwarding and POP/IMAP tab and select Enable IMAP right beside IMAP access.
5. Click Save Changes.

   

In addition to this, enabling Allow Less Secure Apps will feature the user to get rid of this error since Microsoft Outlook client may be recognized as a less secure app by Google, sometimes.

Note: Make sure you do not have 2-Step Verification enabled before enabling this feature because in case you have it enabled, this option will not be available for you with a notification ‘This setting is not available for accounts with 2-Step Verification enabled. Such accounts require an application-specific password for less secure apps access’ as shown below.

1. While still logged in, navigate to Google Security page from your web browser.
2. Scroll down to find Less secure app access and click on Turn on access (not recommended) to enable this feature.

   

    

3. Try logging into Microsoft Outlook client. This issue should now be resolved.

Solution 3: Generate an App-specific Password (if 2-Step Verification is Enabled)

As discussed before, you can not enable Allow Less Secure Apps feature by Google mail services if you have extra-security check i.e. 2-Step Verification enabled. In this case scenario, the user must generate an App-specific password before he/she can log-in on your Microsoft Outlook client. Follow the given procedure in doing so:

1. Open the Gmail Log-in page from your web browser.
2. Log-in to Gmail with your account details.
3. While still logged in, navigate to Google Security page from your web browser.
4. Navigate to Signing in to Google and click on App passwords.

   

5. Confirm your sign-in again to proceed further.
6. Click on Select app > Other (Custom name) .

   

7. Type Outlook and hit Generate.

   

8. This will generate an app password for your device. Copy the generated 16-character password.

   

9. Use this password for signing into your Microsoft Outlook. This should fix your issue.

Solution 4: Check your Microsoft Outlook Configuration

As mentioned before, 78754 failure may occur if Microsoft Outlook is not configured correctly. To make sure if it is configured correctly, follow:

1. Click Start or press Windows key, search Outlook and hit Enter.

   

2. Now enter your email address, click on Advanced options and check Let me set up my account manually and hit Connect.

   

3. Select IMAP (for Windows 10 Operating System) or POP or Google on other Windows versions.

   

4. Ensure that IMAP or POP access is turned on (It should already be done while following solution 2 steps) before attempting to add your Gmail account on Microsoft Outlook client.
5. Use the given server information to configure your Microsoft Outlook client correctly.
   

   Incoming mail

   Server: imap.gmail.com
   
   Port: 993
   
   Encryption method: SSL/TLS
   
   Require logon using Secure Password Authentication (SPA): Unchecked

   

   Outgoing mail

   Server: smtp.gmail.com
   
   Port: 465
   
   Encryption method: SSL/TLS
   
   Server timeout: One bar
   
   Require logon using Secure Password Authentication (SPA): Unchecked
   
   My outgoing (SMTP) server requires authentication: Checked
   
   Use same settings as my incoming mail server: Checked

   

6. You will be required to enter your log-in credentials. Put your correct information and click Connect. This should fix your error.

Solution 5: Update your Microsoft Outlook

As we know, sometimes, an outdated Windows cause troubling errors forbidding the proper functionality of Windows applications and features. Similarly, any outdated application can behave the same way. Therefore, upgrading your email client (Microsoft Outlook) to the latest version might just simply fix your problem. If none of the solutions have worked for you, this finally should. Follow the given procedure to do so:

1. Click Start or press Windows key, search Outlook and hit Enter.
2. Navigate to File and click on Office Account.

   

3. Click Update Options, select Update Now from the drop-down menu.

   

4. This will automatically find updates for your Microsoft Outlook client and install them.
5. To make sure you are updated to the latest version, you should see the following message when you repeat the same procedure.