Why aren't 2 external monitors working with MBP (mid 2014)?

So I have 2 external monitors; One is hdmi, the other is DisplayPort.

I have a MBP mid-2014 model which contains 2 Thunderbolt 2 ports as well as an HDMI port.

Theoretically I would have thought I could plug in two miniDP to HDMI cables, run one to monitor #1, and run the second one to an HDMI to DisplayPort adapter -> monitor #2.

That did not work, and I since realized only one of the miniDP ports can support video at a time.

I then read running an HDMI and a miniDP at the same time would work, so I tried that, miniDP->HDMI monitor #1, and then HDMI->HDMI to DP adapter -> monitor #2. Still does not work. Only one monitor shows video.

For the life of me, I cannot figure out why this is so difficult to do. I have seen others use USB adapters but would prefer not to sacrifice any CPU usage with the second display.

What possible options do I have for using my 2 external monitors in extended view?

Thank you for any help!

According to Apple, your MBP supports dual monitors plus the native display:

https://support.apple.com/kb/sp703?locale=en_US

You may have a bad HDMI>DP adapter, but my bigger question is why are you doing that in the first place? Why take Thunderbolt and convert to HDMI, when you have a HDMI port on the Macbook?

I recommend that you connect the HDMI port to the HDMI port on one monitor, and you connect the Thunderbolt to DP on the other monitor. Thunderbolt outputs DP 'natively' so its a better fit for DP.