eWarrior

Your problem is likely either in the Mac mini, the OS, the cable or the monitor. For troubleshooting, my first step would be trying a different monitor. Then using a different hdmi cable If neither one of these options alleviates the connection problem, I would start worrying about the Mac mini. I have used a first gen Mac mini as a single use audiobook source for my home network for years, and it still accepts absolutely every monitor I have ever needed to attach it to. So - have the nerds inspect your cable connections. If monitor and cable is fine, the problem could be the input connector on the Mac mini, but that would make it unlikely that another monitor would work. Frankly, in your case, with a reasonably modern Mac mini, my approach would be to simple get a second hand monitor that works and let it go (provided the simple troubleshooting above doesn’t reveal anything useful.