Grey Circle with white bar through it - help?

Hi Using Norton Internet Security v18.6.0.29 - Win7 Pro (32bit)

been a Norton user for 10 years+ and have many products on it. However I can't find out anywhere what the change in my icon bar means - grey circle with white line through it (usually a green tick).

Any help or suggestions as to how to return the green tick? Checked for updates, run scan, restarted - all no change :(

Thanks, Colin