monitor displays shows no picture in display settings and goes black randomly
Assuming your cable is connected securely at both ends, the first thing to try is connecting the HP V270 display to a different USB-C port to see what difference, if any, this makes.

If this has no effect then I'd reset your NVRAM.

Resetting the NVRAM

Your Mac uses Non-Volatile Random-Access Memory (NVRAM). To reset the NVRAM on your MacBook Pro model follow these steps:


Shut down your machine. Yes, a full shut down, so go to Apple > Shut Down so you’re not just logging out.
Press the power button (in your case this is the Touch ID button) and then immediately press the commandoptionpr keys. 
Keep these keys pressed down for at least 20 seconds!
Let go of the keys and let your Mac reboot normally.


Note: When you log back in you may need to readjust some of your system preferences (e.g. speaker volume, screen resolution, startup disk selection, time zone information, etc).

If you still have problems after doing this, let me know.



Since resetting the NVRAM and swapping the ports has had no real impact, I'd strongly recommend testing your display with another computer and/or trying a different cable. 

In terms of the MacBook Pro itself, you could use Apple Diagnostics to test its hardware for some peace of mind. You can do this as follows:


Fully shut down your MBP
Restart your MBP
Immediately press the D key and keep it down until you see the Diagnostics screen appear
Wait for Diagnostics to finish (this typically only takes a few minutes)
Once complete, one of two things will appear on the screen:


a No issues found message
a brief description of any errors found plus further instructions

If the diagnostics test does find errors, take a note of what they are


Note: If pressing and holding the D key at Step 3 doesn't work, start again at Step 1 and, at Step 3 press and hold both the OptionD keys instead. This will try and run diagnostics from the internet instead, so you will need to allow more time for it to complete.