NextcloudPi with own Domain does not load in internal network

I bought a domain name for my NCP server after getting a FritzBox 7530. Before that I had a different Router and used a subdomain provided by freedns. To reach the new domain I linked it successfully via ddns (from freedns) with my router.

Now I can access my NC server from the external network but not in my internal network. I just recieve a “The connection has timed out” error.

I already set the domain ( in the “rebind protection exemption list” and set up the dnsmasq server in the NCP configuration.

I put the internal IP of my raspberry in the dnsmasq configuration box for the dns server. Is that correct or do I need to use a different IP?

Any idea what is causing the NC not being accessible in my internal network @home?

I am running a similar setup (NextcloudPi behind AVM-Fritzbox 3490). As far as i remember, adding the domain to the “DNS rebind protection”-list is the one and only thing i did.
There is no need to use dnsmasq (at least i never used it).