Problems such as these occur when Outlook is running in the background. Press CRTL ALT DELETE and open use your app manager to stop Outlook from running before trying to continue.

You can update in numerous way. Start by getting your hands on any version of Outlook On Desktop, and visit the menu once the software is installed. Click the option that says, “Check for Updates,” and update your program that way. You may also visit the official Outlook On Desktop website and download the most modern version, but this is more difficult than simply checking for updates via the software itself.

It is usually because of a bug relating to your current version of Outlook. One solution is to update either your OOD software or your Outlook. Some people have more luck by going back to older builds of either software.