Managed Challenge plugin - log missing config

Author: webprofusion-chrisc

src/Certify.Providers/DNS/CertifyManaged/DnsProviderCertifyManaged.cs

@@ -200,6 +200,12 @@ public async Task<bool> InitProvider(Dictionary<string, string> credentials, Dic
             _log = log;
             _parameters = parameters;
 
+            if (_credentials == null || _credentials.Count == 0)
+            {
+                _log.Error("Certify Managed Challenge DNS Provider could not be created: credentials missing or not set for managed challenge API.");
+                return false;
+            }
+
             if (parameters?.ContainsKey("propagationdelay") == true)
             {
                 if (int.TryParse(parameters["propagationdelay"], out var customPropDelay))
@@ -219,6 +225,11 @@ public async Task<bool> InitProvider(Dictionary<string, string> credentials, Dic
 
                 _client.BaseAddress = _apiBaseUri;
             }
+            else
+            {
+                _log.Error("Certify Managed Challenge DNS Provider could not be created: managed challenge API URL not set.");
+                return false;
+            }
 
             return await Task.FromResult(true);
         }