Cloudflare + Caddy SSL issue

Just need some help with my homeserver, this my first time doing this so have been stumped many times. Essentially I am running Proxmox with 2 VM's, one for TrueNAS (which has Treafik and Nextcloud) and the other with Debian (for Jellyfin). Ever since I have configured Caddy in debian (have tried disabling treafik and removing the ports for it), both of my domains (a.example.com and b.example.com) have both displayed an Error 526: Invalid SSL certificate.

The domain was bought, registered and configured in Cloudflare and there wasn't an issue when it was only Nextcloud. Also to note that this happens when Caddy/Jellyfin on deb is configured not if the URL is one of another provider (i.e DuckDNS).

Thanks for any help :)