All router topologies are backwards compatible, so the type and channel shouldn’t matter.
First question: Do you have MAC Address filtering enabled on your router? If you do, then turn that off and reboot your router, as it will prevent unknown devices from being issued an IP address, even if the password is correct.
I’m using a Core, but I’m also a newbie, so let’s work on this together.
Are you using a Mac or a PC?
I assume you’ve got the PARTICLE-CLI installed?
Is this a brand-new Photon, or has it ever connected somewhere else?
Have you logged into “the cloud” using both PARTICLE LOGIN and PARTICLE CLOUD LOGIN commands? (I don’t know if this helps, but it is reassuring to know that at least your account works!)
The reason I had to do multiple factory resets was that this was the only way I could get my device to connect. I’d factory reset, it would reboot and blink greenish-yellow, then I’d force the blue listening mode and perform a “PARTICLE SETUP” and it would work fine - until I removed the power, then it would go back to being a blinking brick again.
After two factory resets, I updated the firmware. The Core is slightly different from your Photon. My Core updates using a program called the “DFU-Utility” which I downloaded from a Particle link, with Core-specific binaries I got from GitHub. I do not believe tht this process applies for your chip: the Photon is supposed to automatically update itself over-the-air after you first connect.
So on to a few more questions:
Does your Wifi have a strong signal? Sorry, probably a basic question, but I have to ask!
I had better luck once I told it to use a specific network and 802.11G rather than having it scan the network for SSID’s. I live in a place with heavy Wifi traffic, so fewer options seemed safer to me 
Have you ever tried a factory reset?
Source: https://docs.particle.io/guide/getting-started/modes/photon/#troubleshooting-modes
A factory reset isn’t anything to fear, and I’m hopeful it may fix your issue. After every failed setup attempt, I’d reboot, then perform another factory reset, so “start over from the beginning”.
Here is the process from that link. for a Photon, step by step:
Procedure:
The procedure is same as the one described above (DFU Mode), but in this case you should continue holding down the SETUP button until you see the device change from flashing yellow to flashing white. Then release the button. This will take about 10 seconds. The device should begin after the factory reset is complete.
To perform a factory reset:
Hold down BOTH buttons
Release only the RESET button, while holding down the SETUP button.
Wait for the LED to start flashing magenta, then yellow, then green (continue to hold the SETUP button)The LED will turn solid white (continue to hold the SETUP button)
Finally, the LED will turn blink white rapidly.
Release the SETUP button