Sending notifications using C# with Nuget package "FirebaseAdmin" version 2.4.0 doesn't work.
ERROR: Invalid value at 'message.android.notification.event_time'.

Our currently working FirebaseAdmin version is 1.1.4 and that is using the legacy cloud messaging API. Because of the migration to the new API which need to happend before june 2024, we updated to the latest FirebaseAdmin 2.4.0 that uses the new api with versioning "/V1". We earlier used "SendAllAsync", but are now trying to use "SendEachAsync" do to deprecation.

Our current AndroidConfig looks like this:

Android = new AndroidConfig
{
    Notification = new AndroidNotification
    {
        ClickAction = "FLUTTER_NOTIFICATION_CLICK",
        ChannelId = "fcm_default_channel",
        Icon = "ic_notif",
        EventTimestamp = DateTime.UtcNow //Added afterwards cause of error but didn't resolve our issue.
    },
    CollapseKey = "type_a"
},

Somehow the EventTimestamp is not working properly. Any suggestions?