So I too hit the ERR_TOO_MANY_REDIRECTS that other users of cloudflare have also hit.
I fixed it by following one of the tips from this post: Community Tip - Fixing ERR TOO MANY REDIRECTS , namely changing the SSL type from Flexible to Full.
However in the interim I did some testing and I found the redirect loop is only being introduced for visits to the root on certain blog platforms. Visits to other sites that use static pages and visits to specific blog posts off the root work fine. i.e. going to blog.mydomain.com (as either http or https) geberates the error. visits to blog.mydomain.com/page or blog.mydomain.com/tag/sometag or anything else works fine as will going to www.mydomain.com
This was tested using ghost, but it seems to be a problem with wordpress as well. I’m not clear precisely why but as I can reproduce it at will and by checking the logs on my server I see that it doesn’t get the requests itself as the whole thing is cached by cloudflare (or rather the redirect is generated by it directly).
Specifically this does not generate a hit on my local server:
<p>Moved Permanently. Redirecting to <a href="https://example.blog.com/">https://example.blog.com/</a></p>
shows a hit in the blog log file AND returns the correct html. Also a curl to https://static.blog.com/ which is hosted on the same physical device and passes through the same argo tunnel works fine
If any cloudflare engineer wants to troubleshoot I can tell you precisely how to do it - in fact they can just follow the instructions here - Micronetia Setup and then tweak the ssl settings in the cloudflare dashboard from flexible to full and back again