I also suffered from this issue too. All traffic via CF using TLS 1.0 was closed.
EXCEPTION: System.Net.Http.HttpRequestException: An error occurred while sending the request. —> System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. —>
To force this on us without notification is unacceptable.
They state on the status page:
SSL for SaaS Issues
Resolved - This incident has been resolved.
Oct 27, 09:52 UTC
Investigating - Cloudflare is investigating issues related to certain SSL for SaaS custom hostnames not being accessible over HTTPS. We are actively working to resolve this issue.