Hi!
I think your issue is similar to this one: DNS Domain Not Connecting - #2 by Lucian_Dinu
Just make sure that those Sitejet A records (similar for the CNAME) are not proxied (they are DNS only) in Cloudflare.
Basically, Sitejet can’t verify the settings because they are “hidden” by Cloudflare.
You have to wait for a few hours after you disabled the proxies (this is not instant).
Also, it will take a while (about 24 hours) for the SSL on the Sitejet side, so … until then, the https links will not work …
Hope this helps!