Ports Forwarded & Active, Yet Friends Get Timed Out/Can't See Game

Hello. I am currently having issues with my router and game hosting for my friends.

I have had my router self-restart last night. (Note: before the restart had happened, my friends were able to connect to all of the games that I had been running personal servers on and set ports forwarded for.) I woke up this morning to see the internet was back, so I started a multiplayer game up and tried to have them connect, yet they timed out on login. They then tried to find my server on server lists and were not able to see it anymore. We tried direct connect with my IPv4 address, and no luck. I restarted the router, the ports remained open afterwards. They were then able to connect and play with me for about 40 minutes before they were all disconnected and told that they 'timed out'. Then they were not able to see my server or connect. Back to square one, then repeat. Also, I am unable to see the games that they host but everybody else can after they get disconnected.

My PC firewall has the games unblocked, and so does Cox's firewall. I can no longer host servers for us to have relaxation time during this period of having to stay indoors because after a short amount of time they are kicked off connection automatically. This problem spans out to all of the games we play on. What is happening and how do I fix this issue? Thank you.