SSL working except for me and one person, been 3 days

[KamilDev]

So, I’m hosting kamildev.net on InfinityFree. I first enabled the cPanel Cloudflare, and SSL was working fine and took effect just in an hour.

Then I realized using the cPanel integration won’t let you have SSL for subdomains, so I disabled the cPanel integration and then re-added my site to Cloudflare manually so I could have more freedom.

It’s all set up good again, SSL and Cloudflare checker all says everything is working good. However, it’s been ~3 days and seems for my whole network my website’s SSL isn’t working (says no SSL certificate, maybe thinking it still points to the old nameservers)

I’ve checked every device I have, cleared DNS cache, still nothing and it’s been 3 days. All my friends say SSL is working fine for them, however finally one of my friends said SSL isn’t working (probably same issue as me)

I decided to connect to a VPN, and behold, the SSL works, so it must be something messed up/cached in my network. My router is Archer VR1600v

Please help me ASAP, thank you.

[sdayman]

If your network will let you specify custom DNS, then I recommend 1.1.1.1 & 1.0.0.1, and/or 9.9.9.9. At least give those a try and see if that fixes the problem.

Some device setup instructions here (scroll down the page a bit):
https://1.1.1.1/help

[KamilDev]

I’ll give it a try soon, though I was hoping to understand why this is even happening in the first place.

EDIT: Changing to 1.1.1.1 DNS worked, though definitely would like to understand why this happened normally. Perhaps my ISP has a bad DNS provider?