If you are using Microsoft Office Outlook on a Windows computer and have encountered an error message The connection to Microsoft Exchange is unavailable, Outlook must be online or connected to complete this action, here are some solutions that may help you resolve the issue. This error mainly occurs when you have added a @yourdomain.com type of email account to Microsoft Outlook, but you may use these suggestions even if you have not used such a form of email address.
The connection to Microsoft Exchange is unavailable
1] Recreate Outlook profile
Whenever you add a new email account in Outlook, it saves the account as a Profile. Sometimes, due to some internal problems, your profile may get corrupted. In this case, you can get the same error message – and the solution is to re-create the profile.
To recreate your Outlook profile, open Control Panel and change the view to either Large icons or Small icons. Following that, click on the Mail (Microsoft Outlook). You will see a window, where you need to click on Show Profiles. Next, select the existing profile and click on the Remove button to remove it.
Now, click the Add button and go through the screen options to add your new account or create a new profile.
Once you have removed and added te Outlook Profile, restart your Outlook. The problem should have gone away.
2] Restore Registry settings
This is a bit tricky, but it would be easier if you follow all the steps carefully. To perform this step, you need two computers running the same Windows OS and version of Outlook.
Now open the Registry editor on the other computer where Outlook is working smoothly. Navigate to the following path:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
Right-click on the User Shell Folders and select Export.
Choose a location where you want to save the .reg file and save it accordingly.
Now copy the file to the computer on which you are facing issues.
Now, press Win+R, type regedit to open the Registry Editor. Then, click on File > Import. Select the .reg file that you have copied recently to add the information to your system.
Hope this helps!