I have a 27" Samsung monitor, purchased in Dubai on 8 May 2020, and shipped back to the US (with all of my other "stuff" in August of 2020). It is now showing two vertical black lines no matter the source (two different laptops) or cables (two different HDMI cables). I've removed all possible external sources of interference and still no luck in resolving the issue.
https://www.flickr.com/photos/191020759@N08/shares/7Eui28
https://www.flickr.com/photos/191020759@N08/shares/7Eui28