Lost network after installing connman

Question

I'm on Ubuntu 16.04, I wanted to try connman so I ran:

Apt-get install connman

After it finished I lost my internet. I restarted the computer and I no longer have the network icon in the top right.

I tried uninstalling connman and restarting with no success.

I also tried restarting network manager.

Service network-manager stop
Service network-manager start

When I open the network settings application I get "The system network services are not compatible with this version".

Answer 1

First I had to reconnect to the internet using the following steps:

1. List all network devices with ifconfig -a (in my case it was wlo1)
2. Turn device on sudo ifconfig wlo1 up
3. Manually use device to scan wifi sudo iwlist wlo1 scanning saw my wifi Prk
4. Associate device with wifi sudo iwconfig wlo1 essid Prk
5. Give device an IP sudo dhclient wlo1

Then I reinstalled network-manager which seemed to revert the broken settings:

sudo apt-get install network-manager

Answer 2

The answer given by Philip Kirkbride didn't work for me. It appears my device had become blocked with RFkill. I'm running Ubuntu 19.04. Here are the modified steps I followed:

1. List all network devices with ifconfig -a, look for wireless interface. In my case it was wlp3s0.
2. Attempt to turn device on sudo ifconfig wlp3s0 up. This returned an error message related to RFKill.
3. List rfkill info with rfkill list all, this shows that the "Wireless LAN" device was indeed marked with

Soft blocked: yes
Hard blocked: no

4. Unblock all devices with rfkill unblock all 5 Running rfkill list all now shows Wireless LAN device changed to unblocked
5. Reboot and the issue was resolved

Note, I attempted to follow steps 3, 4 and 5 in the answer by Philip after rfkill unblock all, but these produced errors in my case.