New iMac is having issues connecting to WiFi

I have an old iMac which I'm replacing with a new one. I've migrated everything from the old to the new machine. I'm essentially running them in parallel for a few days, to make sure everything looks OK, but generally speaking, the old iMac is turned off.

At the moment, my old machine is still directly connected to my router. The new machine is connecting by wifi, mainly because I do not yet have the proper cable connector to directly connect the new machine. I had no difficulties for the first few days, but today I'm having trouble connecting to the Internet with the new machine.

Initially, when I tried to access any URL, the new machine did not even appear to be trying to connect. There was no spinning status indicator and when I hit the reload button, it cleared the URL I had entered, as if *no* URL had been entered yet.

Eventually, one of the pages I tried to load did try to load, but at the moment, it's been spinning for about 15 minutes. No connection has been made yet.

Curious, I turned the old iMac back on and tried to connect to the Internet with its direct connection. I'm typing this note from the old machine, as it had no difficulty loading any given page.

Since I had no problem for the first three days or so, I assume there is something up with my service, that the wifi connection cannot load, but the direct connection *can*.

My plan is to directly connect the new machine to the router, once I get a new cable or pick up a connector convertor from the old to the new. But until then, I'd like to troubleshoot the wifi connection. However, I don't know where to look for that, as I saw very little that could help me diagnose the situation in the Network System Preferences information.

Still spinning on the new machine....

[Re-Titled by Moderator]