OpenBoard return code: -1

Hi,
I would like to create a package with the OpenBoar application https://github.com/OpenBoard-org/OpenBoard/releases/download/v1.3.6/openboard_ubuntu_16.04_1.3.6_amd64.deb

I created the AppImage package but when I start it I get the following error:
```
Error: Error executing 'usr/bin/OpenBoard'; return code: -1
```
This is verbose log:

```
Desktop file: /home/antonio/OpenBoard/OpenBoard.AppDir/openboard.desktop
Name: OpenBoard
Icon: OpenBoard
Exec: usr/bin/OpenBoard %f
Comment: OpenBoard, an interactive white board application
Type: Application
Categories: Education;
File used for determining architecture: /proc/self/exe
Arch: 86_64
App name for filename: OpenBoard
dest_path: OpenBoard-x86_64.AppImage
/home/antonio/OpenBoard/OpenBoard.AppDir should be packaged as OpenBoard-1.3.6-x86_64.AppImage
WARNING: AppStream upstream metadata is missing, please consider creating it
in usr/share/metainfo/openboard.appdata.xml
Please see https://www.freedesktop.org/software/appstream/docs/chap-Quickstart.html#sect-Quickstart-DesktopApps
for more information.
Generating squashfs...
Size of the embedded runtime: 97112 bytes
Parallel mksquashfs: Using 4 processors
Creating 4.0 filesystem on OpenBoard-1.3.6-x86_64.AppImage, block size 131072.
[============================================================================================================================-] 2391/2391 100%

Exportable Squashfs 4.0 filesystem, gzip compressed, data block size 131072
compressed data, compressed metadata, compressed fragments, compressed xattrs
duplicates are removed
Filesystem size 25875.89 Kbytes (25.27 Mbytes)
43.37% of uncompressed filesystem size (59669.56 Kbytes)
Inode table size 22103 bytes (21.58 Kbytes)
26.86% of uncompressed inode table size (82280 bytes)
Directory table size 21720 bytes (21.21 Kbytes)
37.07% of uncompressed directory table size (58593 bytes)
Number of duplicate files found 786
Number of inodes 2526
Number of files 2104
Number of fragments 113
Number of symbolic links 2
Number of device nodes 0
Number of fifo nodes 0
Number of socket nodes 0
Number of directories 420
Number of ids (unique uids + gids) 1
Number of uids 1
root (0)
Number of gids 1
root (0)
Embedding ELF...
Marking the AppImage as executable...
Success
```

Where am I wrong?

Antonio