P2419H, not connecting to MacBook Pro

@hratchye  What specific MacBook Pro are you using?  There are 3 sizes and multiple generations, all of which are different.  And are you connecting both of the displays using a USB-C to HDMI cable?  Do they each work if you connect them separately and you only have a problem when you connect them at the same time?  If it's one specific display that never works, have you tried swapping the cables and the port on the MacBook Pro side to eliminate variables?  Please be specific about exactly what cabling setups you're testing, in addition to providing more detail about your system.  When asking for technical assistance, it helps to provide basic technical information so that the people here who are willing to help have something to work with.

My work computer is a 2020 13" MacBook Pro with a 2 GHz quad core intel core i5 processor. My personal computer is a 2018 15" MacBook Pro with a 2.2 GHz 6-core intel core i7 processor. The monitor does not work with either of these computers. I have tried the cables in both of my monitors and they are not the problem. I have tried all 4 ports in each computer and that isn't the issue either. I tried the Run the Self test and Built in Diagnostics tests in the Dell manual and those didn't yield any results either. I have tried connecting both monitors at the same time and individually but the one monitor still doesnt recognize the HDMI to USB-C adaptor. Any help/insight is appreciated.

@hratchye  I realize this is a basic question, but I ask because sometimes people miss this: Have you set the non-working display to the actual HDMI input? For that matter are you even able to bring up the onscreen menu, or can you not even get the display to show that? Have you tried any other HDMI source devices, like a cable box, steaming box/stick, game console, DVD player, etc.? If you can’t get any source to work even after making sure the display is on its HDMI input, then it could be a problem with the input or the entire display. Given that the display has a DisplayPort input, you could try a USB-C to DisplayPort adapter/cable. That’s actually simpler anyway since USB-C uses DisplayPort for video to begin with. USB-C to HDMI adapters/cables need to incorporate active signal converter chips to switch that signal over to HDMI.