Stéphane, you are fortunate that the Online Content Catalogue remains active and available for XDPXv11.
That said when I open mine, I too get 504 Server errors:
You have to persevere through this for a time and then you should be able to access the Online Content with Insert > From Content Catalogue.
If you can do this then you can go to your Designs gallery and right-click on all the blue folders in turn and pick Download All.
Once you have down this, you can consider disconnecting from Internet access.
To do this, open C:\Program Files\Xara\Xara Designer Pro X11 and rename the Online to Online - Disconnected.
This means you probably can still access the Catalogue but the nags should disappear.
Acorn
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