Randomly IPV4 sites wont load but IPV6 sites are fine. Any suggestions? This is driving me insane.

I had a Comcast employee come out and he checked all my lines and he checked my connection to their servers and all looked good but the IPV4 sites were still not loading. We tried 2 different computers. It appears I can get it work sometimes when I realease and renew the IP but I am not sure if thats just a coincidence. My IP address also seems to be static. Any suggestions would be greatly appreciated since I am a streamer and I need the internet for my business.