Inacccessable admin page

[Nuetronium]

Hi everyone,

I have a TS-453A on 4.2.2 that's directly connected to my computer via Ethernet using the 169.254.100.100 address. Mapped drives, ssh, Qfinder are all still working (can send to sleep, wake on LAN etc), business as usual except the admin page doesn't load. Network is fine, the PC has a static IP for the interface the qnap in connected to (169.254.100.101), correct subnet, can ping etc. Tried connecting over Firefox, Chrome, Opera and Edge getting the same results. After entering the IP, I get the site is not secure, I add an exception, secure connection failed (or 'page isn't working', error differs on each browser). Rebooting the NAS or the PC does nothing. I haven't setup SSL certs or previously had issues assessing the admin page.

Any idea's on how to resolve?