Mac WiFi sharing doesn't allow LAN discovery?

I've been using Mac Mini for a few years as a WiFi router by enabling network sharing over WiFi. Everything until now has worked fine.

The problem is that my MBP can't auto discover shared folders on the Mini, even though it comes up on the MBP's "Shared" list in Finder. When I click on the Mini in the MBP's finder, it tries to connect but then ends with a "Connection failed" message. However, if I try to connect manually using the "Connect to Server" command in Finder, it works fine.

Another possible symptom is that my iPhone4S when connected to the same WiFi network can't automatically find the MBP, at least when using apps that have local sync capabilities.

I've checked to make sure all the network settings are the same on the MBP and the iPhone when connecting to the WiFi network. The Macs are running the latest Yosemite and the iPhone's running the latest IOS 8.

Anyone having the same issues?