error: Code="InvalidRequestFormat" Message="Cannot parse the request." Details=[]

using N = Pulumi.AzureNative.Network;
using NI = Pulumi.AzureNative.Network.Inputs;

 var privateEndpoint = new N.PrivateEndpoint("privateEndpoint", new N.PrivateEndpointArgs
        {
            Location = location,
            ManualPrivateLinkServiceConnections = 
            {
                new NI.PrivateLinkServiceConnectionArgs
                {
                    GroupIds = 
                    {
                        "sites",
                    },
                    PrivateLinkServiceId = apiAppService.Id,
                    RequestMessage = "Please manually approve my connection.",
                },
            },
            PrivateEndpointName = "Pulumi-PEP",
            ResourceGroupName = platformResourceGroupName,
            Subnet = new NI.SubnetArgs{
                Id = subnetApps01.Id,
            },
        });