Copilot Studio_Adaptive card issue_Property cannot be Null

[pu3aiesya]

Hi all, below is my JSON for my adaptive card in copilot studio.
I got an error saying that : Property cannot be null?
{
"type": "AdaptiveCard",
"body": [
{
"type": "TextBlock",
"size": "Medium",
"weight": "Bolder",
"text": "FREQUENTLY ASKED QUESTION [FAQ]",
"horizontalAlignment": "Center"
},
{
"type": "Image",
"url": "https://static.wixstatic.com/media/6e51ea_b20110d8e8c04018813c6d859273c14f~mv2.gif"
},
{
"type": "TextBlock",
"text": "Here are some available topics which you can dive in and have a look first.",
"wrap": true,
"separator": true
},
{
"type": "Input.ChoiceSet",
"choices": [
{
"title": "Access",
"value": "Access Issue"
},
{
"title": "LPN",
"value": "Missing LPN 2"
},
{
"title": "Status",
"value": "Change Request Status"
},
{
"title": "FAQ",
"value": "FAQ"
}
],
"placeholder": "Select an option"
}
],
"$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
"version": "1.5",
"actions": [
{
"type": "Action.Submit",
"title": "Submit",
"iconUrl": "https://pngimg.com/d/buttons_PNG151.png"
}
]
}

[jwoo-msft]

@pu3aiesya,

Can you provide more information about copilot studio?

It does appear that it's specific to copilot studio as this card works in our designer.