One of my websites (pc-builder.net) is having this issue for some of the customers. On Chrome it shows up as ERR_SSL_PROTOCOL_ERROR, and on Firefox it’s SSL_ERROR_RX_RECORD_TOO_LONG. I can’t reproduce the error locally but for some people it’s very consistent.
One weird thing is that, if they use a VPN, the error goes away for some reason. It seems like a problem with Cloudflare, please take a look into this!
The error is showing up in CURL as “connection reset by peer” well which means that it’s not a problem with browsers. And this is happening even after I moved the site to a different account, so, it’s not because of a configuration error as well.