Remote Access Issue-Resolves but fails reachability

I’m trying to set my NextBox up so that it allows Remote Access, but have run into some difficulties following the instructions at Remote Access Walkthrough — Nitrokey Documentation
I got through steps 1-7 without any issues. but had to do some guessing to set up Port Forwarding and may have done something incorrectly.

When I check the Nextbox app>Remote Access - Status

I see
Successfully resolved: xxxx.dedyn.io to: xxxx[IPv4]

Failed reachability for: xxxxx, xxxx.dedyn.io[IPv4]Please see the following topics at docs.nitrokey.com/nextbox to troubleshoot: Port-Forwarding/Firewall router settings, (Dynamic) DNS

Successfully resolved: xxxx.dedyn.io to: xxxxx:3[IPv6]

Failed reachability for: [xxxxx::3], 1[IPv6]Please see the following topics at docs.nitrokey.com/nextbox to troubleshoot: DNS-Rebind Protection, (Dynamic) DNS

The NextBox is successfully resolving, but fails reachability for both IPv4 and IPv6 - but I don’t understand what that means.

I looked at the help topics referenced, but don’t understand what I need to do. If it could be explained at a more beginner level, how I can correct this I would appreciate it.

Thanks in advance.

While trying to get Port Forwarding to work, I seem to have messed something else up.

I’m not exactly sure what I changed, but now when I try to go to nextbox.local I get the message " This site can’t be reached

nextbox.local’s DNS address could not be found. Diagnosing the problem.

DNS_PROBE_POSSIBLE"

same thing when I try to go directly to the DNS address that was working earlier.

Anyone know where I may have messed things up or how to fix it?
Can I start over from Step 1 with the Nextbox and try again? is there a better way? Throw it in recycling?

I’m running out of ideas and haven’t heard back from the support email, which is frustrating.