Connecting HDMI to Ubuntu causes problems

I have an external monitor but it only supports VGA and my laptop only HDMI. So, I got an HDMI to VGA converter. Now, whenever I connect my laptop to the monitor the laptop's display goes off.

But weirdly enough it's not actually off, I can still move my mouse in and all the windows open on the laptop's screen are still there on the laptop's screen.

So I go to the 3rd terminal shell in Ubuntu by pressing Ctrl+Alt+F3 and restart the gdm service using sudo service gdm3 restart (this has worked out for most display problems in past, so why not)

But the problem becomes even worse, the laptop display is now turned on, but none of the window works, I mean I can't click on any of them, I can move the mouse and see it move but that's the only thing I can do. Everything else is stuck.

The problem does get fixed after I restart my laptop with the HDMI attached to it.

The output of sudo lspci -vvv|grep -A 11 'VGA ':

01:00.0 VGA compatible controller: NVIDIA Corporation GP104M [GeForce GTX 1070 Mobile] (rev a1) (prog-if 00 [VGA controller])
Subsystem: Dell GP104M [GeForce GTX 1070 Mobile]
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0
Interrupt: pin A routed to IRQ 141
Region 0: Memory at dc000000 (32-bit, non-prefetchable) [size=16M]
Region 1: Memory at b0000000 (64-bit, prefetchable) [size=256M]
Region 3: Memory at c0000000 (64-bit, prefetchable) [size=32M]
Region 5: I/O ports at e000 [size=128]
[virtual] Expansion ROM at 000c0000 [disabled] [size=128K]
Capabilities: [60] Power Management version 3