diff --git a/code/gms-backend/src/main/java/io/github/gms/common/dto/ErrorResponseDto.java b/code/gms-backend/src/main/java/io/github/gms/common/dto/ErrorResponseDto.java
index ad90ee45..2a644fa8 100644
--- a/code/gms-backend/src/main/java/io/github/gms/common/dto/ErrorResponseDto.java
+++ b/code/gms-backend/src/main/java/io/github/gms/common/dto/ErrorResponseDto.java
@@ -1,11 +1,15 @@
 package io.github.gms.common.dto;
 
+import com.fasterxml.jackson.annotation.JsonFormat;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import lombok.Data;
 
+import java.io.Serial;
 import java.io.Serializable;
 import java.time.ZonedDateTime;
 
+import static io.github.gms.common.util.Constants.DATE_FORMAT;
+
 /**
  * @author Peter Szrnka
  * @since 1.0
@@ -14,10 +18,12 @@
 @JsonInclude(JsonInclude.Include.NON_NULL)
 public class ErrorResponseDto implements Serializable {
 
+	@Serial
 	private static final long serialVersionUID = 6418018474049813605L;
 	
 	private String correlationId;
 	private String message;
+	@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = DATE_FORMAT)
 	private ZonedDateTime timestamp;
 
 	public ErrorResponseDto(String message, String correlationId, ZonedDateTime timestamp) {
diff --git a/code/gms-backend/src/test/java/io/github/gms/GmsExceptionHandlerTest.java b/code/gms-backend/src/test/java/io/github/gms/GmsExceptionHandlerTest.java
index 87a77c08..59711975 100644
--- a/code/gms-backend/src/test/java/io/github/gms/GmsExceptionHandlerTest.java
+++ b/code/gms-backend/src/test/java/io/github/gms/GmsExceptionHandlerTest.java
@@ -6,7 +6,6 @@
 import io.github.gms.common.exception.GmsException;
 import org.jboss.logging.MDC;
 import org.junit.jupiter.api.BeforeEach;
-import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.springframework.core.MethodParameter;
 import org.springframework.http.HttpStatus;
@@ -29,7 +28,6 @@
  * @author Peter Szrnka
  * @since 1.0
  */
-@Disabled
 class GmsExceptionHandlerTest extends AbstractUnitTest {
 
 	private static final String CORRELATION_ID = "CORRELATION_ID";
@@ -101,7 +99,7 @@ void shouldHandleMissingRequestHeaderException() {
 		WebRequest webRequest = mock(WebRequest.class);
 
 		// act
-		ResponseEntity<ErrorResponseDto> response = handler.handleOtherException(new MissingRequestHeaderException("x-api-key", mockMethodParameter), webRequest);
+		ResponseEntity<ErrorResponseDto> response = handler.handleMissingRequestHeaderException(new MissingRequestHeaderException("x-api-key", mockMethodParameter), webRequest);
 
 		// assert
 		assertNotNull(response);
diff --git a/code/gms-backend/src/test/java/io/github/gms/TestApplicationConfig.java b/code/gms-backend/src/test/java/io/github/gms/TestApplicationConfig.java
index 42e0e1c7..0a0ead6d 100644
--- a/code/gms-backend/src/test/java/io/github/gms/TestApplicationConfig.java
+++ b/code/gms-backend/src/test/java/io/github/gms/TestApplicationConfig.java
@@ -5,6 +5,7 @@
 import org.springframework.boot.CommandLineRunner;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;
 
 /**
@@ -13,6 +14,7 @@
  */
 @Slf4j
 @Configuration
+@ComponentScan(basePackages = "io.github.gms")
 public class TestApplicationConfig {
 
 	@Bean