Setting up a router to run off another router

Hello all,

I’m in a bit of a pickle. I tried running a router off of another router last night and got internet for all of 30 minutes until it ultimately stopped receiving internet. The second router is run from a 300 ft. Cat 6 cable going from the first router. I gave the 2nd router a new IP and disabled DHCP in order to prevent IP conflicts in case they crossed paths. I need some help to determine if it’s an issue with the length of the cat 6 cable and that it just ultimately won’t send the internet speeds I need or is there some settings with the 1st and/or 2nd router I can change in order to keep a constant connection on the 2nd router. Any help would be greatly appreciated. Sorry, kinda noob at this stuff.