Audacity device toolbar is empty

I am using Audacity on Ubuntu 16.04 to record from an electric piano through an input jack. My laptop recognized the recording device and I can see input levels fluctuating when I play from my keyboard (although I can’t hear anything). The device toolbar in audacity is empty. When I hit the record button it gives the following message:
“Error opening sound device. Try changing the audio host, recording device and the project sample rate”

I’ve already tried re-installing my sound drivers. Does anyone know what’s going on?

What sort of electric piano, and what is the “input jack” that you refer to?

How does your laptop show that?
What is the recording device?

Where do you see that?

What options do you have? In a default Ubuntu set-up there is only one option.

How did you do that?

(Re-installed Alsa)

If Device Toolbar or Devices Preferences show no playback and/or recording devices, this means there are currently no audio devices available to, or recognized by Audacity. There are a few possible causes of this.

You don’t have the correct permissions to access the sound device, perhaps because you need to add your user to the “audio” group.

If your system does not use PulseAudio or if you choose the (hw) device in Device Toolbar, another audio application, sound server or service is using the sound device. You will need to disable applications or services that are using the device before Audacity can access it, or share the device among applications using JACK.

If you choose the OSS host (where available) in Device Toolbar, you must check that /dev/dsp (the OSS device) is present.

Read more at Missing features - Audacity Support