If Outlook cannot connect to your mail server, you may see an error code instead of receiving or sending emails. You can troubleshoot errors that are commonly caused by incorrect account settings, internet connectivity problems, damaged Outlook profiles, or security software blocking the connection.
This guide will help you troubleshoot common email error messages in Microsoft Outlook and Outlook Express when using your 1-grid email account.
By following the steps below, you’ll be able to identify the most common causes and resolve many Outlook connection issues without needing to contact support.

What This Means
When Outlook or Outlook Express displays an error code, it usually means the email application cannot successfully communicate with the mail server.
This does not necessarily mean there is a problem with your mailbox or your 1-grid hosting service.
In most cases, the issue is caused by:
- Incorrect email account settings
- Internet connectivity problems
- Damaged Outlook profiles
- Firewall or antivirus software
- Corrupted emails waiting on the server
- Damaged Outlook installation
Understanding the cause can significantly reduce the time needed to restore your email service.
Steps to Troubleshoot Outlook Errors
Step 1: Check Your Internet Connection
Before troubleshooting Outlook, confirm that your device is connected to the internet.
Try:
- Opening several websites
- Running an internet speed test
- Restarting your router if required
IMPORTANT: If your internet connection is unavailable, Outlook will not be able to connect to your mail server.
Step 2: Verify Your Email Account Settings
Incorrect account settings are one of the most common causes of Outlook errors.
Check that your:
- Email address
- Username
- Password
- Incoming mail server
- Outgoing mail server
- Port numbers
- Encryption settings
match the settings supplied by 1-grid.
If you recently changed your email password, update it in Outlook as well.
Step 3: Restart Outlook
Close Outlook completely.
Wait a few seconds before reopening the application.
Temporary connection issues can often be resolved with a simple restart.
Step 4: Check Your Antivirus and Firewall
Some antivirus or firewall software can prevent Outlook from communicating with the mail server.
Temporarily disable email scanning (if appropriate) or review your security software settings to ensure Outlook is allowed to connect.
If disabling your antivirus resolves the issue, re-enable it afterwards and adjust the configuration instead of leaving it disabled.
Step 5: Repair or Recreate Your Outlook Profile
If the problem started suddenly and your settings are correct, your Outlook profile may have become corrupted.
Try:
- Repairing the email account
- Removing and re-adding the email account
- Creating a new Outlook profile
Removing and recreating an account usually does not delete emails already stored in Outlook, although it’s always recommended to have a backup before making significant changes.
Step 6: Check for Corrupted Emails
Occasionally, a damaged email stored on the server can prevent Outlook from downloading new messages.
If available, log in to your mailbox using Webmail and check for unusually large or corrupted emails.
Delete or move suspicious emails and then try syncing Outlook again.
Step 7: Repair or Update Outlook
If Outlook itself is damaged:
- Install the latest Office updates.
- Run the Microsoft Office Repair tool.
- Restart your computer after repairs have completed.
Common Outlook Error Codes
The following Outlook error codes are commonly associated with connection or mail server problems:
- 0x800CCC15
- 0x80042108
- 0x800CCC0E
- 0x8004210B
- 0x800CCC0B
- 0x800CCC79
- 0x800CCC67
- 0x80040900
- 0x800CCC81
While these codes indicate different connection failures, the troubleshooting steps above resolve many of the underlying causes.
Important Things to Know
- Outlook Express is a legacy Microsoft application and is no longer supported by Microsoft.
- Many Outlook errors are caused by incorrect account settings rather than server issues.
- Security software can interfere with email connections.
- Temporary network interruptions may trigger connection errors.
- Some issues require Outlook profile repair rather than mailbox changes.
Before You Move On
Before contacting 1-grid Support, make sure you have:
- Verified your internet connection.
- Confirmed your email settings.
- Restarted Outlook.
- Checked your antivirus and firewall configuration.
- Recorded the exact Outlook error code.
- Tested whether Webmail works successfully.
Common Mistakes to Avoid
- Entering incorrect incoming or outgoing server settings.
- Using an outdated email password.
- Ignoring the full Outlook error code.
- Leaving antivirus software disabled after testing.
If This Didn’t Work
If you’re still unable to send or receive emails, please collect the following information before contacting 1-grid Support:
- Your domain name
- Your email address
- The Outlook error code
- A screenshot of the error message
- Your Outlook version
- Whether the issue affects sending, receiving, or both
- Confirmation that Webmail works (if tested)
Providing this information allows us to investigate your issue much faster.
Related Articles
- I Can Browse the Internet, but I Cannot Get My Email
- I Am Getting a “Please Enter Network Password” Error Message
- Recipient Address Rejected When Sending Email
- Maximum Email Size for Sending and Receiving
- Email Account Configuration Settings
FAQs
What causes Outlook error codes?
Most Outlook error codes are caused by incorrect email settings, internet connectivity problems, damaged Outlook profiles, or security software blocking the connection.
Is the problem always with 1-grid?
No. Many Outlook errors occur on the local computer rather than the mail server.
Can antivirus software stop Outlook from working?
Yes. Some antivirus applications inspect email traffic and may accidentally block Outlook from connecting to the server.
Will recreating my Outlook account delete my emails?
In most cases, no. However, it’s recommended that you back up important emails before making changes to your Outlook profile.
Why does Webmail work when Outlook doesn’t?
Do these troubleshooting steps fix every Outlook error code?
Not every error has the same cause, but these checks resolve many of the most common Outlook connection issues.
Empowering Insight

Many Outlook error messages are caused by configuration issues on the local device rather than problems with your mailbox. Troubleshoot Outlook email errors by carefully checking your settings. Often, connection restores email access without needing technical assistance.
Need Additional Support?
If you’ve completed the troubleshooting steps above and Outlook still cannot connect to your mailbox, the 1-grid Support team is ready to assist.
Contact us with the Outlook error code, screenshots, email address, and domain name available so we can investigate as quickly as possible.