• Check server requirement from settings
• Another possible solution is to check the server requirement from settings.
• To get it started, open Microsoft Outlook first.
• Then go to the top menu bar select File. 
• Now click the Account Settings drop-down menu and then select the Account Settings option.

In the Account Settings, make sure you’re on the E-mail tab, then double-click on your email account. Once the Change Account window appears, click the More Settings button (in the bottom-right corner) to continue.

This will open a new wizard named Internet E-mail Settings. Switch to the Outgoing Server tab and mark the checkbox next to My outgoing server (SMTP) required authentication.

Now click the OK button to save the changes.

Once you complete the procedure, restart the application and see if it works.

Delete duplicate accounts

Duplicate accounts are also one of the reasons for the occurrences of this error. So, if you have also a duplicate account, delete it and check if it helps you to get rid of this issue.

• To do this, open File > Account Settings.
• Using the drop-down menu, click Account Settings again.
• Inside the Account Settings window, make sure you’re on the E-mail tab.
• Now select the duplicate account from the list and hit the Remove button.
• In the confirmation dialog box, click on the Yes button.
• After following steps properly, restart Outlook and check if the problem is solved now.

Change server port number

It is suggested that whenever you encounter this kind of problem you should change the server port number. Here are the steps to get you started:

• Open Outlook and then go to File > Account Settings.
• Click the drop-down menu and select Account Settings from the popup menu.
• In the Account Settings, go to the E-mail tab and then double-click on your account.
• Once the Change Account window opens, go to the bottom-right corner and hit the More Settings button.

This will open a new window named Internet E-mail Settings, click on the Advanced tab. Under Server Port Numbers, change the Outgoing server (SMTP) port number to 587.

Now click on the OK button to save the changes.

Once you complete the steps, restart the application and check if it resolved the problem.

Repair Outlook

Sometimes this type of problem is temporary and only restarting it will fix the problem. Although, if it doesn’t work, try to repair the application using the below instructions:

• Open the Windows Settings using the Win+I keyboard shortcut.
• Inside the Settings window, select Apps > Apps & features.
• Under Apps & features, scroll through the list and select the Office Product you want to repair.
• When you select the application, you will see a Modify option there, click on it.
• On the next page, select the radio button next to the Repair button and then hit Continue.
• Now follow the on-screen instructions to proceed with the repair process.

Once you complete it successfully, restart Outlook and try to send the email again.

Re-install Outlook to fix Error 0x800ccc0e

If the problem is still persevering, in such a case reinstallation of the Outlook can possibly resolve the error.

To do so, open the Control Panel first and then go to Programs and Features.

• From the list of programs, locate the Office 365 and then right-click on it.
• Select the Uninstall button from the context menu.
• If UAC prompts on the screen, click Yes to give the approval.
• Now follow the on-screen instructions to complete the uninstallation process.
• This will successfully remove the Office app from your device.

Now it’s time to install Office 365 on Windows PC again.

When you complete the steps, check if you’re now able to send and receive the email again.