Unable to communicate with one of my Synology NASs

After taking my network down to re-cable everything, HA no longer communicates with one of them. I removed it and tried to re-add it. It gets discovered by HA, but I cannot get past the authorisation part (no errors, just comes back to submit prompt). From HA, I can ping the IP address, but if I try to CURL a response from its API it just times out. What’s confusing me is that HA has discovered that the NAS is there, so must be extracting some sort of response? I’m beginning to feel that this is a Synology problem, as it seems to be blocking access on port 5001 to HA. Any thoughts greatly appreciated.

Sounds like a auto blacklist to me, check the IP list in Synology

I’ve done that. I’ve since tried using port 5000, rather than 5001 and that works. My gut feeling is that the Synology certificate expiring, and being regenerated has something to do with it.

if you acces on 5000 and tick ‘don’t validate ssl’ that would not be applicable

Try disabling the Synology firewall, if it then works, you have a firewall config problem.