Is there a way to check connection status of an API?

Question

My workteam created a MVC Application integrated with an API for school project. This API is connected to n APIs.

I want to do HttpGet from the "main" API which will ask all APIs to make HttpGet in order to obtain lists from each one of them. I want this to work even if some APIs are offline but ... How can I check their internet connection through their Uri before making those Http requests? I tried to ping the API but I found some problems

public async Task<List<Booking>> GetAvailable(DateTime start, DateTime end)
{
        var uriList = new List<string>();
        var availableList = new List<Booking>();
        var hotelList = await _repo.FindAllAsync();
        
        foreach (var hotel in hotelList)
        {
            uriList.Add(hotel.Uri);
        }
        foreach (var uri in uriList)
            {
                if(ServerConnected(uri))
                {
                    using (var client = new HttpClient())
                    { 
                        client.BaseAddress = new Uri(uri);
                        client.DefaultRequestHeaders.Accept.Clear();
                        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                        (...)
}
                
(...)

public static bool ServerConnected(string url)
     {
        Ping pingSender = new Ping();
        var reply = pingSender.Send(url);

        if (reply.Status == IPStatus.Success)
        {
            return true;
        }
        else
            return false;
    }