I have two routers and a switch. Router 1 is the Verizon modem/router combo. Router 2 is a Netgear Nighthawk configured as an AP. I need to put a switch in between the two of them (for my PC to connect to) because the Nighthawk is only letting about 400mbps/1gb through. If I go from R1 to the MS, it won't connect or come online - won't even show any link light activity. When I take that same uplink and plug it into R2 WAN port, it comes online instantly. I checked port configurations/event log and can't see anything. I factory reset the MS and still nothing. It's brand new out of the box. Any ideas on what I may be missing?
Given that the link light never comes on, I'm with @PhilipDAth and @BlakeRichardson thinking it's a L1 problem and to try another known good patch cable between the MS Switch and Router1. Also of course, try plugging Router1 into different switch ports on the MS, it's possible there could be a bad port. Should be quick and simple to try 2 different patch cables on 2 different ports on the MS. Also confirm if Router1 might be locked to a specific speed/duplex setting, such as 1000/full, and make sure the MS switch port where it's plugging into as locked to the same settings, just in case something is not auto-negotiating properly.
Also, was Router1 previously connected to something else, where it might have configured a sticky MAC whitelist and won't allow anything else to connect except the original device that was learned? Even if not, perhaps try rebooting and/or factory resetting Router1, while it's plugged into the MS switch and see if at ANY point the MS port shows an active link. If you've identified a bad port on the MS you'll need to open a ticket with Meraki Support anyway, so might as well open a ticket to get another set of eyes looking at this with you.
Initially, I thought it was a L1 problem but I tried a new cable from Router1 to MS and still nothing. I also tried every port on MS and can't get any link lights - however any other device in MS works fine. There have been no configurations made to Router1 as it's just a normal Verizon gateway that no one's ever logged into but I will try to login and poke around to see if it could be blocking it in any way. Thank you guys for the input - I will post back when I find something.