"threat secured" popup when going to a website ive always went to

I use a program to monitor airplanes in my area and as of yesterday when i view it, i keep getting a popup of “threat secured” whenever it tries to retrieve stock airplane photos from www.airport-data.com. Is there a reason why airport-data.com is blacklisted and is there a way i can remove it from the list so i dont keep getting these popups? Thanks


https://i.ibb.co/nfRYvD3/virtual-radar-virus-threat.jpg


https://i.ibb.co/rFnP69Y/Clipboard01.jpg

is there a way i can remove it from the list so i dont keep getting these popups?
https://forum.avast.com/index.php?topic=14433.msg1289438#msg1289438

thanks Pondus