Help with www.subdomain

[Ral]

I am having issues accessing my www.subdomain via Cloudflare.

I added parent domain bitsmart.it. This works.
www.bitsmart.it works.
I have a sudomain mainwp.bitsmart.it. This seems to work as it redirects to www.mainwp.bitsmart.it (as per WP config), however then I get the error

"Secure Connection Failed

An error occurred during a connection to www.mainwp.bitsmart.it. Cannot communicate securely with peer: no common encryption algorithm(s). Error code: SSL_ERROR_NO_CYPHER_OVERLAP"

I have a DNS configured as such
a: bitsmart.it -> 45.63.31.179
cname: www -> bitsmart.it
a: mainwp -> 45.63.31.179
cname: www.mainwp -> mainwp.bitsmart.it

Can anyone advise what I may have done wrong?

Thanks

[sandro]

The naked domain and “www” seem to work fine. “mainwp” also works fine, however it redirects to “www.mainwp” which wont work on Cloudflare with a default certificate.

[Ral]

OK. Thanks for that. So does that mean i need to upgrade to a paid account that includes a certificate? Or just use without www?

[sandro]

Either.