[sandbox] create l2connections

[API_User]

Hello !
I'm trying to create l2 connection on sandbox but i have some error

$ curl -X POST -H "Content-Type: application/json" "https://sandboxapi.equinix.com/ecx/v3/l2/connections" -H "Authorization: Bearer xxxxxx" -d '{
"primaryName": "test_port_crea_1",
"primaryPortUUID": "a9d0254e-d856-4a53-b105-7178fede119f",
"primaryVlanSTag": 601,
"profileUUID": "1bef8e6b-ea90-4757-bb25-c24f9d64387c",
"authorizationKey": 444111000222,
"speed": 200,
"speedUnit": "MB",
"notifications": [
"sandboxuser@example-company.com"
],
"purchaseOrderNumber": "312456323",
"sellerRegion": "us-east-1",
"sellerMetroCode": "SV",
"namedTag": "Private"
}'

Returns

[{"errorCode":"IC-LAYER2-400","errorMessage":"Required field","moreInfo":"","errorMessageKey":"IC-LAYER2.IC-LAYER2-400","property":"additionalInfo_custBGPAssn"}]

I couldn't find documentation about this field on documentation

- https://developer.equinix.com/content/api/buyerv3-recommended?view=product-catalog#/Layer%202%20Conn...

Could you held me ?
Best regards
Louis