I can access my AI assistant only through Acrobat Web app, but I cannot find the option in the desktop app. I have a creative cloud subscription and the AI plan added separately.

Thanks for posting, ​@Giulio Morandini ! I can confirm that your subscription for AI Assistant is active. Are you trying to access the AI assistant, in the desktop app, using the method described at https://helpx.adobe.com/acrobat/desktop/use-acrobat-ai/set-up-acrobat-generative-ai/access-in-acrobat.html?

Is the computer or network managed by an organization?

If not, check to make sure that any installed security software is up to date and using the manufacturer's settings. The AI assistant feature requires different network connections than those you previously used in the desktop app. Misconfigured software could be blocking the desktop app from seeing the active subscription.

If the computer or network is managed, then please update this discussion so that the necessary information can be provided to allow the computer to access Adobe’s online services.