Remote doesn't work on newly installed Ubuntu Machines

**Describe the bug**
New installations of Ubuntu 20.04, 21.04 and 19.04 fails to work with remote access

**To Reproduce**
Steps to reproduce the behavior:
1. Install Ubuntu
2. Install the agent
3. Scroll down to'
4. Get error:
root@mj-HVM-domU:/usr/local/bin/Remotely/Desktop#
root@mj-HVM-domU:/usr/local/bin/Remotely/Desktop# Dec 29 16:49:41 mj-HVM-domU Remotely_Agent[21909]: Attempting to launch screen caster with username mj, xauthority /home/mj/.Xauthority, display 192.168.60.61, and args -u mj /usr/local/bin/Remotely/Desktop/Remotely_Desktop -mode Unattended -requester "a14534f1-b4e2-4704-841b-cead033e73c6" -serviceid "XXXXXXXXXXXXXXXXXXXXXXX" -deviceid XXXXXXXXXXXXXXXXXXXXX -host "https://remote.mrmeee.dk" -orgid "XXXXXXXXXXXXXXXXXXXXXXXX".
Dec 29 16:49:41 mj-HVM-domU sudo[21927]: root : PWD=/usr/local/bin/Remotely ; USER=mj ; COMMAND=/usr/local/bin/Remotely/Desktop/Remotely_Desktop -mode Unattended -requester a14534f1-b4e2-4704-841b-cead033e73c6 -serviceid XXXXXXXXXXXXXXXXXXXX -deviceid XXXXXXXXXXXXXXXXXXXXXX -host https://remote.mrmeee.dk -orgid XXXXXXXXXXXXXXXXXXXXXXX
Dec 29 16:49:41 mj-HVM-domU sudo[21927]: pam_unix(sudo:session): session opened for user mj by (uid=0)
Dec 29 16:49:41 mj-HVM-domU kernel: Remotely_Deskto[21928]: segfault at e0 ip 00007f0dff85eda4 sp 00007fff1dd68db8 error 4 in libX11.so.6.4.0[7f0dff84e000+8c000]
Dec 29 16:49:41 mj-HVM-domU kernel: Code: 07 48 03 b7 e8 00 00 00 48 8b 46 10 c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 8b 87 e0 00 00 00 c3 0f 1f 44 00 00 f3 0f 1e fa <48> 63 87 e0 00 00 00 48 c1 e0 07 48 03 87 e8 00 00 00 48 8b 40 10
Dec 29 16:49:41 mj-HVM-domU sudo[21927]: pam_unix(sudo:session): session closed for user mj

I have a Ubuntu 21.10 which has been running for a year, and there it works fine, so I expect it to be some kind of dependency??

If I compile the Desktop part by myself, and put it in.. I get this error instead..:

Dec 29 16:54:51 mj-HVM-domU sudo[21976]: root : PWD=/usr/local/bin/Remotely ; USER=mj ; COMMAND=/usr/local/bin/Remotely/Desktop/Remotely_Desktop -mode Unattended -requester a14534f1-b4e2-4704-841b-cead033e73c6 -serviceid XXXXXXXXXXXXXXXx -deviceid XXXXXXXXXXXXXXXXXXX -host https://remote.mrmeee.dk -orgid XXXXXXXXXXXX
Dec 29 16:54:51 mj-HVM-domU sudo[21976]: pam_unix(sudo:session): session opened for user mj by (uid=0)
Dec 29 16:54:51 mj-HVM-domU Remotely_Agent[21977]: XOpenDisplay failed
Dec 29 16:54:51 mj-HVM-domU Remotely_Agent[21977]: XOpenDisplay failed
Dec 29 16:54:51 mj-HVM-domU Remotely_Agent[21977]: Unhandled exception. System.Exception: XOpenDisplay failed
Dec 29 16:54:51 mj-HVM-domU Remotely_Agent[21977]: at Avalonia.X11.AvaloniaX11Platform.Initialize(X11PlatformOptions options) in /_/src/Avalonia.X11/X11Platform.cs:line 57
Dec 29 16:54:51 mj-HVM-domU Remotely_Agent[21977]: at Avalonia.AvaloniaX11PlatformExtensions.<>c__0`1.b__0_0() in /_/src/Avalonia.X11/X11Platform.cs:line 266
Dec 29 16:54:51 mj-HVM-domU Remotely_Agent[21977]: at Avalonia.Controls.AppBuilderBase`1.Setup() in /_/src/Avalonia.Controls/AppBuilderBase.cs:line 303
Dec 29 16:54:51 mj-HVM-domU Remotely_Agent[21977]: at Avalonia.Controls.AppBuilderBase`1.Start(AppMainDelegate main, String[] args) in /_/src/Avalonia.Controls/AppBuilderBase.cs:line 157
Dec 29 16:54:51 mj-HVM-domU Remotely_Agent[21977]: at Remotely.Desktop.XPlat.Program.Main(String[] args) in /home/mj/Hentet/remotely-agent/Desktop.XPlat/Program.cs:line 33
Dec 29 16:54:51 mj-HVM-domU sudo[21976]: pam_unix(sudo:session): session closed for user mj

**Remotely Version**
Server 2021.08.26.1335:
Agent 2021.08.26.1335:

**Expected Behavior**
Remote connection to open

**Additional Context**
Hope you can help..

Start by reproducing the failure on the Ubuntu versions named in the report, using the logged agent launch command. Inspect Desktop.XPlat/Program.cs and the Avalonia.X11 stack shown in the trace, then compare the packaged and locally compiled Desktop behavior. Done means the remote connection opens without the reported segfault or XOpenDisplay failure.

Written by the indexing model from the issue text.