Networking conundrum

Paul,
Another thought, try setting up another user account on your MBP and see if that can hold the connection to the mini. - If so, then it may be a problem with your network preferences.

Oh, that’s a good thought. Thanks. I’ll try that.

Powerline adapters can be sketchy as part of it depends on the electrical cabling in the walls for your house - if there is a cross-over somewhere it can throw of the data flow direction. (this is me speaking as a non-expert, but with some poor real-world experience with powerlines networks in the past).

Yep, I get where you’re coming from, but I can’t see it being a problem with the powerline connection. For one thing, only one of the devices I’m unable to connect to is connected by powerline (the NAS is a direct ethernet connection to the router). For another, the other devices in the house can connect to the powerline-connected device, even while mine can’t - and even mine can connect if I use the wifi extender network instead of the main wifi. It’s got to be something to do with either the router or my computer, and having reset the router I figure it’s gotta be my computer.

So, I set up two new accounts - one with my appleID (so should auto-connect to other devices with the same appleID), and one with no appleID at all. Neither one of them could connect to either the mac mini or the NAS over the main wifi network - with the one that didn’t have the AppleID, I didn’t even get the dialogue come up that asks me to enter credentials for registered user or guest. For both devices, in both users, I just got a long pause and then a message that ‘there was a problem connecting to [device].’

Maybe it is the router after all. It might be due for replacement.

So, I took the plunge and got a new router. Problem solved.

I was surprised to find out that my Fritzbox 7390 was nine years old! Not bad for a piece of tech these days. I got a brand new 7490, and all has been running smoothly for over a week now.

Thank you all for your contributions. It was a very perplexing case.