Website will not load SSL_ERROR_NO_CYPHER_OVERLAP

I am currently trying to get a site live on cloudflare for a worldwide company.

The error in Firefox is SSL_ERROR_NO_CYPHER_OVERLAP.

I’ve signed up for a Pro account because i read that the SSL then gets verified in 15 minutes rather than 24 hours.

The site is still not working.

Any ideas would be greatly appreciated as it is imperative we get this site live ASAP.