I'm sorry to hear you're facing issues with the new Mockup feature. To better assist you, could you please provide a screenshot of your Illustrator's performance settings from the preferences menu?
Also, to further diagnose the problem and see if there's any potential solution, the product team has requested the "AISniffer" file from your system. Please locate and share this file as requested:
Navigate to the following folder on your computer:C:\Users\<username>\AppData\Roaming\Adobe\AdobeIllustrator27Settings\<locale>\x64
You should find the "AISniffer" file in this location.
This information will help them understand your system configuration better and further investigate this.
Thank you for your patience and cooperation in this matter. If you have any further questions or need additional assistance, please don't hesitate to ask.
Thank you for your response, i guess the issue is with Vram, its not as per Illustrators requirement. Not sure why illustrator requires 1Gb or higher for the mockup to function.