If when you go on to Send/Receive, Reply, Reply All or Forward an email in Microsoft Outlook on your Windows 10/8/7 computer, you receive a Not Implemented error box, then here are a few things you should look at.
Not Implemented error in Outlook
1] If you receive this error, the first think you want to do is repair or reinstall your Microsoft Office installation. Office 2016 on Windows 10 does not allow you to uninstall individual components, and so you need to carry out either a Quick Repair or an Online Repair. Users of earlier Office versions can uninstall, reinstall or repair individual Office programs.
2] Start Outlook in Safe Mode. To do this, open the Rin box, type outlook /safe and hit Enter. If it runs fine, you may want to check the installed add-ins. Disable some Outlook add-ins and see if that helps you.
Click File menu > Options > Add-ins > Go button besides Manage: Com-in Add.
Try to identify the offending addon and disable it. Restart Outlook and try.
3] Reset the Outoolk srs file. This file contains the settings that you set using the via the CTRL+ALT+S Send/Receive Groups settings. To do this, close Outlook and navigate to the followig folder:
Delete the Outlook.srs file that you see. When Outlook restarts, the file will be automatically re-created.
4] Create a new Outlook Profile and check if it helps.
5] The following posts give additional ideas:
Hope something helps!