I changed my router some time ago. When I recently tried to open my Synology NAS in a browser, DSM wouldn’t load even though Finder could still connect to all my shared folders.
Once I reached it, DSM told me:
You are not authorized to use this service.
Then Safari and Chrome behaved differently, and the NAS thought it was 1 January 2016. It looked like one big failure, but it was actually several smaller problems stacked together.
Finder Working Fooled Me
My old network used 192.168.50.x. The NAS had kept its manually configured address, 192.168.50.2, even though the new router used 192.168.68.x.
The old address was unreachable from the new network. Finder still worked because it had discovered the NAS through Bonjour and connected over local IPv6.
Finder working only proved that some path to file sharing was alive. It didn’t prove that IPv4 was configured correctly.
Moving the NAS Onto the New Network
I temporarily gave my Mac a second address in the NAS’s old network. That let me reach DSM and change the NAS to 192.168.68.71, with the correct subnet mask and gateway for my new router.
After that, both DaNas.local and the direct IP opened DSM again. Don’t copy my addresses though, use an unused address that matches your own router’s network.
If this happens after changing routers, check all 4 network settings on the NAS:
- IPv4 address
- Subnet mask
- Default gateway
- DNS server
“Not Authorized” Was a Different Problem
My administrator account still received the authorization error. Luckily, another MacBook had a working DSM session.
From there I opened Control Panel > Privileges > DSM > Edit and discovered that my user wasn’t allowed to use DSM, despite belonging to the administrators group. I enabled Allow and checked that no Group or By IP rule denied access.
Before resetting anything, check every computer and browser for a session that still works. One logged-in machine saved me from a rather dramatic solution to a checkbox problem.
Safari and Chrome Still Failed
Normal Safari kept showing the same error, but a Private Browsing window logged in successfully. I removed the Synology entry from Safari > Settings > Privacy > Manage Website Data, and normal Safari worked again.
Chrome couldn’t load either the hostname or direct IP, while Brave could. Under System Settings > Privacy & Security > Local Network, my Mac had around 10 Google Chrome entries and most were disabled. I enabled them, quit Chrome with Cmd-Q, reopened it, and DSM loaded.
The Wrong Clock Exposed the DNS Problem
The NAS clock was stuck in 2016, and synchronising with time.google.com kept hanging. It was still using my old router, 192.168.50.1, as its DNS server.
I changed the DNS server to 1.1.1.1 and tried time.google.com again. Synchronization worked immediately.
The real fix was replacing every network setting left behind by the old router, including DNS.
My router didn’t really break the NAS. The NAS was just stubbornly living on my previous network.