This tutorial is deprecated in favour of Fix VERSION_OR_CIPHER_MISMATCH · Cloudflare SSL/TLS docs
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This tutorial covers a possible reason for the SSL_ERROR_NO_CYPHER_OVERLAP and ERR_SSL_VERSION_OR_CIPHER_MISMATCH errors (Firefox and Chrome respectively) when seen on a subdomain.
The Cloudflare universal certificates cover example.com and *.example.com. This means that it covers any subdomain one level below the domain you signed up with.
It will cover www.example.com and subdomain.example.com, as these are one level below the root domain, example.com.
The certificate will not cover www.subdomain.example.com or a.b.example.com, however, as these subdomains are too deep.
Solution:
You either need the $10/month Advanced Certificate Manager from Cloudflare, on which you can specify the subdomain you need to cover, or to set the record to 
and bypass Cloudflare altogether.
If you have or can get a Business or Enterprise plan, you could also upload a custom SSL certificate with the required hostnames.
Links:
Other common issues with SSL/TLS on subdomains:
Deprecated - SSL/TLS not working on subdomain
Advanced Certificate Manager documentation:
Advanced certificates · Cloudflare SSL/TLS docs
Tutorial Reference: CT-11
Reviewed: 07/21
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