iMac WiFi Hotspot not Working I have a late 2009 iMac running 10.12.5 that I am attempting to set up as a wifi hotspot. My current internet connection is DSL (ethernet). 

I finally found a guide online how to actually do this and I follow all the instructions, including setting up a password at the end for security purposes. That went great and both my iPhones (5s and 7) recognized the network. However, when I tried to connect to the network, it said I either needed to restart my modem, router or contact my ISP. I have had this same issue previously when I have tried to make my iMac a hotspot (I had a computer exactly like this one before and had the same issue with it, the other one was running El Capitan though).

My question here is, what am I missing? Why isn't my iMac becoming a hotspot after I have gone through the set up process? Here is the link I used for the instructions to set the hotspot up.
You might have been sharing your connection from a wrong connection. For example, if you are connected via ethernet, and share it over wifi, you have to select the right ethernet port (some computers have more than one with USB or thunderbolt adapters).
Your network has some type of VPN set up, it prevents sharing. OR your ISP simply deployed hotspot request filtering technology. You either have to turn it off, hack it if you know how (looks like you don't), or just move on and not share your connection.
You hardware is broken. Nothing you can do there.
You encounter kext error. Need a full power down and restart.