Crash on "Add station to library"

[bitsandpisces]

Hello everyone
I got Gradio freshly installed (ubuntu 18.04 32b) following instructions from
https://flathub.org/apps/details/de.haeckerfelix.gradio

When I open it, it crashes when clicking on "Add radio stations to library", so I can't add any or listen to a radio station

From terminal :
$ flatpak run de.haeckerfelix.gradio
** Message: 10:38:56.981: gradio-app.vala:192: Gradio 7.1
** Message: 10:38:56.984: gradio-app.vala:200: Locale dir: /app/share/locale
** Message: 10:38:57.082: gradio-app.vala:142: Registered search provider service.
** Message: 10:38:57.091: gradio-app.vala:135: Desktop session is: ubuntu
** Message: 10:38:57.092: gradio-library.vala:75: Open database...
** Message: 10:38:57.093: gradio-library.vala:76: /home/username/.var/app/de.haeckerfelix.gradio/data/gradio/gradio.db
** Message: 10:38:57.093: gradio-library.vala:46: Successfully opened database! Reading database data...
** Message: 10:38:57.243: gradio-main-window.vala:271: Changed page mode to "library"

Can you please help ?

[haecker-felix]

Is that the complete terminal output?

[bitsandpisces]

Yes. After that, it disappears from screen.

[ALPonomarev]

This problem is still relevant.
My terminal reports:
$ flatpak run de.haeckerfelix.gradio
** Message: 22:11:20.109: gradio-app.vala:185: Gradio 7.2
** Message: 22:11:20.111: gradio-app.vala:193: Locale dir: /app/share/locale
** Message: 22:11:20.161: gradio-app.vala:135: Registered search provider service.
** Message: 22:11:20.288: gradio-library.vala:75: Open database...
** Message: 22:11:20.288: gradio-library.vala:76: /home/alexey/.var/app/de.haeckerfelix.gradio/data/gradio/gradio.db
** Message: 22:11:20.288: gradio-library.vala:46: Successfully opened database! Reading database data...
** Message: 22:11:20.438: gradio-main-window.vala:271: Changed page mode to "library"
** Message: 22:11:28.542: gradio-main-window.vala:271: Changed page mode to "collection_items"
** Message: 22:11:29.053: gradio-station-provider.vala:60: Search results found: 14
** Message: 22:11:29.102: gradio-station-provider.vala:60: Search results found: 14
** Message: 22:11:29.111: gradio-station-provider.vala:60: Search results found: 14

Then the program closes