Check Home Assistant configuration AddOn fails

Hello community,

recently I migrated my setup from a RPi to a NUC following the generic linux tutorial with Ubuntu Server 18.04 LTS.

At the moment I’m running HA 91.4 which I also used for the setup on the NUC.
I tried to check the configuration agaionst HA 92.0 but the addons fails with these log entries:

[Info] Start install HomeAssistant latest
  Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f51e304e940>: Failed to establish a new connection: [Errno -3] Try again')': /simple/homeassistant/
  Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f51e304ea58>: Failed to establish a new connection: [Errno -3] Try again')': /simple/homeassistant/
  Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f51e30429e8>: Failed to establish a new connection: [Errno -3] Try again')': /simple/homeassistant/
  Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f51e3042fd0>: Failed to establish a new connection: [Errno -3] Try again')': /simple/homeassistant/
  Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.VerifiedHTTPSConnection object at 0x7f51e3042748>: Failed to establish a new connection: [Errno -3] Try again')': /simple/homeassistant/
  Could not find a version that satisfies the requirement homeassistant (from versions: )
No matching distribution found for homeassistant
[Error] Install HomeAssistant: Collecting homeassistant

I suspect it is realted to either Ubuntu or Docker but I’m quite quite new to both worlds.
Hope that someone can point me into the right direction.

Got it, the problem was DNS resolution for the combination Ubuntu 18.04 and Docker.
This solved my issues.