Photon keeps reconnecting to wifi, maybe router issue

Photon stuck in a loop of connecting to the wifi. It seems to connect and have the breathing cyan, but then it gets weird and reconnects. Here’s the pattern.

breathing cyan
breathing green
3 flashes of cyan
2 flashes of red
flashing green

Photon was working fine before. Big change is that I upgraded our router to an Archer C7. It supports 802.11b/g, but maybe there’s some other issue that’s causing this problem.

Is it running Tinker and doing this.

Nope, can’t run Tinker.