diff --git a/backend/src/main/java/com/vaessl/app/connection/ConnectionProvider.java b/backend/src/main/java/com/vaessl/app/connection/ConnectionProvider.java
index 0b6e893..bd2c7d1 100644
--- a/backend/src/main/java/com/vaessl/app/connection/ConnectionProvider.java
+++ b/backend/src/main/java/com/vaessl/app/connection/ConnectionProvider.java
@@ -5,6 +5,8 @@ import com.vaessl.app.dto.ConnectionResponse;
 
 public interface ConnectionProvider {
 
+    void checkCredentials(ConnectionRequest request);
+
     String getServiceType();
 
     ConnectionResponse authenticate(ConnectionRequest request);
diff --git a/backend/src/main/java/com/vaessl/app/connection/ConnectionService.java b/backend/src/main/java/com/vaessl/app/connection/ConnectionService.java
index 86c3b28..bfd2ace 100644
--- a/backend/src/main/java/com/vaessl/app/connection/ConnectionService.java
+++ b/backend/src/main/java/com/vaessl/app/connection/ConnectionService.java
@@ -8,7 +8,6 @@ import org.springframework.stereotype.Service;
 
 import com.vaessl.app.dto.ConnectionRequest;
 import com.vaessl.app.dto.ConnectionResponse;
-import com.vaessl.app.exception.ProviderNotFoundException;
 
 @Service
 public class ConnectionService {
@@ -27,9 +26,7 @@ public class ConnectionService {
 
         ConnectionProvider provider = providerRegistry.get(request.serviceType());
 
-        if (provider == null) {
-            throw new ProviderNotFoundException();
-        }
+        provider.checkCredentials(request);
 
         ConnectionResponse response = provider.authenticate(request);
 
diff --git a/backend/src/main/java/com/vaessl/app/connection/HomeBoxConnectionProvider.java b/backend/src/main/java/com/vaessl/app/connection/HomeBoxConnectionProvider.java
index fa7117f..051ea85 100644
--- a/backend/src/main/java/com/vaessl/app/connection/HomeBoxConnectionProvider.java
+++ b/backend/src/main/java/com/vaessl/app/connection/HomeBoxConnectionProvider.java
@@ -1,7 +1,9 @@
 package com.vaessl.app.connection;
 
 import java.time.Instant;
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 
 import org.springframework.stereotype.Component;
@@ -9,6 +11,7 @@ import org.springframework.web.client.RestClient;
 
 import com.vaessl.app.dto.ConnectionRequest;
 import com.vaessl.app.dto.ConnectionResponse;
+import com.vaessl.app.exception.EmptyCredentialsException;
 
 import static com.vaessl.app.connection.Endpoint.*;
 
@@ -24,6 +27,22 @@ public class HomeBoxConnectionProvider implements ConnectionProvider {
         this.cRepository = cRepository;
     }
 
+    @Override
+    public void checkCredentials(ConnectionRequest request) {
+        if (request.username() == null || request.password() == null) {
+            List<String> missingFields = new ArrayList<>();
+
+            if (request.username() == null) {
+                missingFields.add("username");
+            }
+            if (request.password() == null) {
+                missingFields.add("password");
+
+            }
+            throw new EmptyCredentialsException(List.copyOf(missingFields));
+        }
+    }
+
     @Override
     public String getServiceType() {
         return "HOMEBOX";
diff --git a/backend/src/main/java/com/vaessl/app/exception/EmptyCredentialsException.java b/backend/src/main/java/com/vaessl/app/exception/EmptyCredentialsException.java
new file mode 100644
index 0000000..62acdc6
--- /dev/null
+++ b/backend/src/main/java/com/vaessl/app/exception/EmptyCredentialsException.java
@@ -0,0 +1,13 @@
+package com.vaessl.app.exception;
+
+import java.util.List;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public class EmptyCredentialsException extends RuntimeException {
+
+    private final List<String> missingFields;
+}
diff --git a/backend/src/main/java/com/vaessl/app/exception/GlobalExceptionHandler.java b/backend/src/main/java/com/vaessl/app/exception/GlobalExceptionHandler.java
index 8bf462b..4e8dd15 100644
--- a/backend/src/main/java/com/vaessl/app/exception/GlobalExceptionHandler.java
+++ b/backend/src/main/java/com/vaessl/app/exception/GlobalExceptionHandler.java
@@ -1,6 +1,7 @@
 package com.vaessl.app.exception;
 
 import org.springframework.http.ProblemDetail;
+import org.springframework.validation.FieldError;
 import org.springframework.web.bind.MethodArgumentNotValidException;
 import org.springframework.web.bind.annotation.ExceptionHandler;
 import org.springframework.web.bind.annotation.RestControllerAdvice;
@@ -10,13 +11,18 @@ import org.springframework.web.client.ResourceAccessException;
 
 import static com.vaessl.app.exception.ErrorMessage.*;
 
+import java.util.stream.Collectors;
+
 @RestControllerAdvice
 public class GlobalExceptionHandler {
 
     @ExceptionHandler(MethodArgumentNotValidException.class)
     public ProblemDetail handleEmptyCredentialInput(MethodArgumentNotValidException e) {
+
+        String defaultMessages = e.getBindingResult().getFieldErrors().stream().map(FieldError::getDefaultMessage).collect(Collectors.joining(", "));
+
         return ProblemDetail.forStatusAndDetail(BAD_REQUEST_EMPTY_FIELDS.getStatus(),
-                BAD_REQUEST_EMPTY_FIELDS.getMessage());
+                BAD_REQUEST_EMPTY_FIELDS.getMessage() + " [" + defaultMessages + "]");
     }
 
     @ExceptionHandler(HttpClientErrorException.Unauthorized.class)
@@ -41,8 +47,9 @@ public class GlobalExceptionHandler {
                         SERVER_ERROR_GENERAL.getMessage() + e.getStatusText());
     }
 
-    @ExceptionHandler(ProviderNotFoundException.class)
-    public ProblemDetail handleWrongServiceType(ProviderNotFoundException e) {
-        return ProblemDetail.forStatusAndDetail(WRONG_SERVICE_TYPE.getStatus(), WRONG_SERVICE_TYPE.getMessage());
+    @ExceptionHandler(EmptyCredentialsException.class)
+    public ProblemDetail handleEmptyCredentials(EmptyCredentialsException e) {
+        return ProblemDetail.forStatusAndDetail(BAD_REQUEST_EMPTY_FIELDS.getStatus(),
+                BAD_REQUEST_EMPTY_FIELDS.getMessage() + " " + e.getMissingFields());
     }
 }
diff --git a/backend/src/main/java/com/vaessl/app/exception/ProviderNotFoundException.java b/backend/src/main/java/com/vaessl/app/exception/ProviderNotFoundException.java
deleted file mode 100644
index a5d8200..0000000
--- a/backend/src/main/java/com/vaessl/app/exception/ProviderNotFoundException.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.vaessl.app.exception;
-
-public class ProviderNotFoundException extends RuntimeException {
-    
-}