Regarding the Cloudflare and Siteground, there are two types of setups with Cloudflare - Full via Cloudflare dashboard directly where you change nameservers to the two the Cloudflare assigns to your domain and Partial Partner offered through a Cloudflare partner where you don’t change to cf nameservers (Siteground example).
Yep, I am getting the same error message from Siteground. CF does say the nameservers can take up to 72 hours to propagate. Glad to hear it now works. Did you change your nameservers in Siteground or did you leave them be?