Why are my emails not being marked as read when I open them?

Check email settings: Double-check that you have enabled the mark emails as read option in your email settings.
Check webmail service: If the email is opened and viewed in a webmail service, refreshed the page or switch off the service and open the emails again.
Check other app: If you’re using a different app to access the emails, check that the app is correctly configured.
Check email client: If you are using an email client, such as Microsoft Outlook, make sure that you have selected the mark emails as read option.
Clear Cache: Clear the cache and/or temporary internet files from the web browser to refresh the page.