Issues connecting to cloudflare

When I connect my site to Cloudflare, the site is working for a bit then I get this error: This site can’t provide a secure connection". I have removed my site and added it back for the same thing to happen. My SSL cert is valid, but I can only get my site back once I disconnect from Cloudflare.
How do I fix this?

It could be related to SSL though you say:

What steps have you taken to resolve? Would you provide further information so that the community members may help you.