We recommend all Gmail users use the Insightly CRM Sidebar.
If you encounter problems with the Classic Insightly Sidebar for Gmail, you might want to disable other extensions that interfere with it or remove and reinstall the sidebar itself.
To remove a Chrome extension, enter chrome://extensions/ in your address bar to access the Extensions page, then click the trash can icon to uninstall an item.
For more detailed instructions, please see Google's directions to install and manage extensions from Chrome.