why does router need to be plugged directly into the wall?

I got a new router because my internet was slow and my ISP recommended getting a new router.

router came in the mail. I thought "this should take just a minute, I have done this before" I even watched a youtube video for my specific router model number to make sure I don't miss anything.

I went to set it up by going to 192.168.0.1 and clicked next next next and every time it would get to the final step, it would produce a generic error, something like "set up was not successful."

I reset the router to brand new and kept trying, same error every time. I even called the manufacturer and got a tech guy on the line who didn't tell me anything I didn't know. He told me to do exactly what I had been doing all day, producing the same error.

3 hours later, I remembered that when I was reading the amazon reviews for a different brand router, someone wrote "this router will not work if plugged into a power strip, it needs to be plugged directly into a wall outlet" (this is the very reason I did not buy that router)

I thought maybe that's the problem. I plugged the router directly into the wall, next next next, set up successful.

Have you ever heard of this problem? Why does this happen? How does the router know it's directly plugged into the wall or through power strip?

Never heard of this.. as there shouldn't be a difference in current between a power strip and wall outlet as they're the same thing basically.

what brand is your router?

You mean a Ethernet port in the wall?

As an Electrical engineer i would say this is not related.

Yeah man, I can't see how that could happen logically. Unless the router's power brick has a special chip in it that detects power bars, but I don't even see how that's possible and that would be a ridiculous thing to have in a product. Electrical output from the power bar and outlet should be IDENTICAL -- 120VAC coming in from wall (or whatever your regional setting) and 120V from the bar sockets. The router would only likely draw 5V - 12V DC anyways, so its not really making sense it would be a power draw / falloff issue.

I agree with others, it was likely a fluke. Perhaps something happened during the time it was unplugged from power bar and plugged into the wall socket -- a reset completed perhaps? Some sort of configuration fully loaded this time? Buggy setup firmware?

Keep in mind in future scenarios, there are usually two types of resets: a "hard reset" and "soft reset". Usually it involves holding down the reset button for a certain amount of time -- and the hard resets usually require hold reset 30 sec plugged in, unplug and keep holding 30 sec, plug back in and hold 30 sec (depends on the device though.) That often resets the NVRAM, that could clear out some bad settings that a soft reset would not. Perhaps you already knew this, but maybe someone else will learn a useful tip

may be just a coincidence ?
No logic behind this

Actually yes it happened with me several times and a friend recommended to just plug the wire directly to a wall outlet and walla it worked. Strangely the previous router didn't work unless I connected the wire with this plug box that is connected to a Land-line.