Using api to generate a video from template, the api result succeeded, but render video failed

curl --location 'https://api.heygen.com/v2/template/0915a2e7701f4c3d9eb11c2e967d0568/generate'
--header 'X-Api-Key: XXX'
--header 'Content-Type: application/json'
--data '{
"caption": true,
"title": "New Video 1",
"variables": {
"script_en_1": {
"name": "script_en_1",
"type": "text",
"properties": {
"content": "FUNCTIONALITY: With the Ninja CREAMi, you can transform everyday ingredients into ice cream, gelato, smoothie bowls, milkshakes, and more..Voltage: 120V-, 60Hz, Power : 800"
}
}
}
}'

Using api to generate a video from template, but never get a success result. always got the result as follows:

Video render failed, we are looking into this issue. Video credits refunded. Contact Us