For about 1-3 months now, I've been unable to connect to either Radarr or Sonarr.

I've verified the correct API, correct internal IP, and port are correct. I've also forwarded the ports in my router.

I've tried emailing support, back in Sept, received no response. Read through the threads here on the forum, none seem to be a closed loop; most seem to end with more questions or confirmation of continuing issues like mine.

If anyone is able/willing to assist with this, I would greatly appreciate it.
Versions of Radarr and Sonarr? Since it is both applications, unlikely to be those.

1. Connection within the LAN all good, so all services run correctly internally.?

2. You are running a simple port forwarding on your router, and there is nothing of note going on there?

3. I appreciate that it is difficult to remember, but no changes on the network since the change. The router isn't new. IP address you are forwarding to internally is static? You control the updates for your router, nothing the router supplier could have updated via auto update?

4. Are you using port forwarding for any other services, or something that you can use to test that an alternate service works.
This issue persists, and it's taken me too long to come back to the forums here to report back, but here I am...

I've recently reset my router (for the umpteenth time), still no luck. There are no restrictions locally, no port forwarding (even with that enabled it wasn't working), and making doubly-sure to carefully input the host IP and port info, still can't connect in the app.

@f3bruary - No, I can't successfully connect via my phone's browser either, so it's definitely an internal network issue. I just can't figure out what.

1. Versions of Radarr and Sonarr are as follows: for Radarr for Sonarr

2. Asked and answered above; even with port-forwarding enabled, I still can't connect successfully.

3. No changes on the network since this began. It befuddles me. I control the network, and have recently gone as far as applying the latest firmware to the router, then resetting, then omitting any custom routing or static IP configuration. I don't really need that anyway, as my HTPC is one of the only things connected via ethernet, and obtains the same IP indefinitely.

4. I do not use any port-forwarding services. I do use a VPN service, but this is disabled on both ends (host and my mobile device) when testing, to be certain it is not throwing a wrench in the whole thing.

I'm legit at a loss here. I loved this app for the time that I had it working. Enough to pay for it, and it's been weeks since I've been able to use and enjoy it.
So here's something that's interesting. Whether we're talking about Sonarr, Radarr, or Lidarr...all 3 have the value of "*" in the Bind Address field under Settings>General. If I input my HTPC's actual IP address in this field and restart the given app...I get an error stating that the port is already in use and to ensure NZBDrone is not running.

Even if I close every last bit of NZB related indexer/manager/service that could possibly be running on my machine, the error still occurs. I also can't access the private IP for the machine from my phone. This extends into another obscure issue in which I can't use Chrome's Remote Desktop feature from my phone unless I switch over to a different network (cell, Xfinity wifi, etc). In other words: somehow, my HTPC has isolated itself in such a way that it is accepting no internal connections, even with no firewall active, firewall exceptions added for everything but the kitchen sink, and seems to only allow RDP connections internally. I'm plum out of ideas on this, as generally I can self-resolve these types of issues.