U3818DW, USB Type-C, stopped functioning, #2

I have had the same issue:

• Out of box, Dell U3818DW worked perfectly with MacBook Pro via USB-C
• I then setup my PC desktop using Displayport
• I switched back to the MacBook Pro, but it can no longer detect the signal
• I disconnected everything and had only the MacBook Pro via USB-C but it no longer worked.
• I tried replacing the cable with another USB-C one from Amazon that someone mentioned worked for them in the reviews, but no luck.
• I can connect my MacBook to the monitor using USB-C/HDMI adapter.