If you still have this issue, here's the fix:
1. Go to your Heroku app, copy the DNS-target for your apex (root) domain (the one that looks like "stark-horse-mrp4jeowu9yvwpnnma32x6hd.herokudns.com")
2. Go to https://www.nslookup.io/, put the DNS target
3. Go through all 5 tabs at the top (Cloudflare, Google, Authoritative) - wherever i you see "A" records - I could only see them in "Authoritative"
4. Copy first A record
5. Go to CloudFlare, replace the flattened CNAME / A record you have for your apex domain with this A record IP you copied
6. Your website should work now, but do the same with the other A records you found as well
7. You should probably revert back to whatever you had in Cloudflare, as soon as Heroku is back up
1. Go to your Heroku app, copy the DNS-target for your apex (root) domain (the one that looks like "stark-horse-mrp4jeowu9yvwpnnma32x6hd.herokudns.com")
2. Go to https://www.nslookup.io/, put the DNS target
3. Go through all 5 tabs at the top (Cloudflare, Google, Authoritative) - wherever i you see "A" records - I could only see them in "Authoritative"
4. Copy first A record
5. Go to CloudFlare, replace the flattened CNAME / A record you have for your apex domain with this A record IP you copied
6. Your website should work now, but do the same with the other A records you found as well
7. You should probably revert back to whatever you had in Cloudflare, as soon as Heroku is back up