Q:

How to set up a Wi-Fi hot-spot on Ubuntu 17.04? 

I recently upgraded from Ubuntu 16.10 to 17.04.  In Ubuntu 16.10, I could setup a WiFi hot-spot to give Internet access to my Android phone using the trick mentioned in this article Share internet with Android Ubuntu 14.04.  I can connect to WiFi now using the fix mentioned in answer to this question: Can't connect to wifi on Ubuntu 17.04.  
But when I click on "Connect to Hidden WiFi Network" and choose to start the hot-spot setup, I see this notification and it doesn't start. 

How should I resolve this? 

A:

I hope this article can help with your problem. 
How to Overcome Ubuntu 17.04 Failed to Make Wifi Hotspot

If Hotspot is on then turn it off first.  Go to System Settings > Network
Turn off Hotspot by clicking ON so it becomes OFF
Click Stop Hotspot
Click All Settings > Software and Updates
Make sure the settings shown are checked. 

Click the Close button and let Ubuntu 17.04 update after entering the password.  Wait for it to finish.  Click Reload. 
Press Ctrl+Alt+T to start the Terminal application. 
Type the following command in Terminal:
sudo apt install hostapd dnsmasq

Go back to the Network window and click Use as Hotspot then click Turn On. 
Hotspot is ON with the name HP-EliteBook-2760p (on my computer)
In order for Android devices to be able to connect to this Hotspot, there is still one more step, namely: 
Click Edit Connections
Select Hotspot then click Edit
Change Mode to Hotspot (provided Ad-hoc)
Click Save
Click Enable Wi-Fi to disable your Wi-Fi
Click again Enable Wi-Fi to enable Wi-Fi

And….  Alhamdulillah ... now Hotspot on Ubuntu 17.04 can function normally.  Android devices can also connect.