Site isn't loading from certain ISPs or locations

Hi, been using the holiday to experiment.

Initially after install (only running: wget -qO ee && sudo bash ee and ee site create --wpredis --letsencrypt) I discovered that Google Page Speed wouldn’t load the page for desktop scan, but would load it for the mobile (though gtmetrix/pingdom loaded it fine).

After trying a number of things I just decided to reinstall and the problem disappeared for whatever reason.

Followed same install and then ran ee site update --php7

However, I then discovered that my site won’t load when browsing from an iPhone on C-Spire wireless data.

On Safari I get “cannot open because it could not establish a secure connection,” using Chrome and Firefox for iphone I get Cloudflare 522 (though i deleted the site from cloudflare and changed the nameservers yesterday)

However, it loads fine on an Android using chrome and Verizon’s network.

Edited for additional info: Also, Pingdom loads fine from every location but Dallas, GTmetrix gives SSL error only occasionally from Dallas as well, but fine for every other location.

Any thoughts?