After turning on my PC, I face the same problem as yesterday. The tray icon of Avira shows a closed umbrella even though the AntiVir Guard is enabled. So, I disable the guard and surprisingly Windows Security Centre does not pop up a message informing that antivirus is not running.
I perform a manual update but receive the error message as shown. In the end, I activate the AntiVir Guard and it shows an open umbrella. The problem is resolved after rebooting PC.