diff --git a/src/main/java/org/springframework/samples/petclinic/rest/advice/ExceptionControllerAdvice.java b/src/main/java/org/springframework/samples/petclinic/rest/advice/ExceptionControllerAdvice.java
index 8d1da3579..5d4848ba2 100644
--- a/src/main/java/org/springframework/samples/petclinic/rest/advice/ExceptionControllerAdvice.java
+++ b/src/main/java/org/springframework/samples/petclinic/rest/advice/ExceptionControllerAdvice.java
@@ -17,6 +17,9 @@
 package org.springframework.samples.petclinic.rest.advice;
 
 import jakarta.servlet.http.HttpServletRequest;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ProblemDetail;
@@ -42,6 +45,9 @@
 @ControllerAdvice
 public class ExceptionControllerAdvice {
 
+    private static final Logger log =
+        LoggerFactory.getLogger(ExceptionControllerAdvice.class);
+
     /**
      * Private method for constructing the {@link ProblemDetail} object passing the name and details of the exception
      * class.
@@ -53,9 +59,12 @@ public class ExceptionControllerAdvice {
     private ProblemDetail detailBuild(Exception ex, HttpStatus status, StringBuffer url) {
         ProblemDetail detail = ProblemDetail.forStatus(status);
         detail.setType(URI.create(url.toString()));
-        detail.setTitle(ex.getClass().getSimpleName());
-        detail.setDetail(ex.getLocalizedMessage());
+        detail.setTitle(status.getReasonPhrase());
+        detail.setDetail("An unexpected error occurred.");
         detail.setProperty("timestamp", Instant.now());
+
+        log.error("Request failed. status={}, url={}, ex={}", status, url, ex.getLocalizedMessage(), ex);
+
         return detail;
     }
 
diff --git a/src/main/java/org/springframework/samples/petclinic/rest/controller/OwnerRestController.java b/src/main/java/org/springframework/samples/petclinic/rest/controller/OwnerRestController.java
index 2a6e008b0..558baa926 100644
--- a/src/main/java/org/springframework/samples/petclinic/rest/controller/OwnerRestController.java
+++ b/src/main/java/org/springframework/samples/petclinic/rest/controller/OwnerRestController.java
@@ -57,9 +57,9 @@ public class OwnerRestController implements OwnersApi {
     private final VisitMapper visitMapper;
 
     public OwnerRestController(ClinicService clinicService,
-                               OwnerMapper ownerMapper,
-                               PetMapper petMapper,
-                               VisitMapper visitMapper) {
+            OwnerMapper ownerMapper,
+            PetMapper petMapper,
+            VisitMapper visitMapper) {
         this.clinicService = clinicService;
         this.ownerMapper = ownerMapper;
         this.petMapper = petMapper;
@@ -99,7 +99,7 @@ public ResponseEntity<OwnerDto> addOwner(OwnerFieldsDto ownerFieldsDto) {
         this.clinicService.saveOwner(owner);
         OwnerDto ownerDto = ownerMapper.toOwnerDto(owner);
         headers.setLocation(UriComponentsBuilder.newInstance()
-            .path("/api/owners/{id}").buildAndExpand(owner.getId()).toUri());
+                .path("/api/owners/{id}").buildAndExpand(owner.getId()).toUri());
         return new ResponseEntity<>(ownerDto, headers, HttpStatus.CREATED);
     }
 
@@ -136,8 +136,12 @@ public ResponseEntity<OwnerDto> deleteOwner(Integer ownerId) {
     public ResponseEntity<PetDto> addPetToOwner(Integer ownerId, PetFieldsDto petFieldsDto) {
         HttpHeaders headers = new HttpHeaders();
         Pet pet = petMapper.toPet(petFieldsDto);
-        Owner owner = new Owner();
-        owner.setId(ownerId);
+        Owner owner = clinicService.findOwnerById(ownerId);
+
+        if (owner == null){
+            return new ResponseEntity<>(HttpStatus.NOT_FOUND);
+        }
+
         pet.setOwner(owner);
         pet.getType().setName(null);
         this.clinicService.savePet(pet);
@@ -175,11 +179,10 @@ public ResponseEntity<VisitDto> addVisitToOwner(Integer ownerId, Integer petId,
         this.clinicService.saveVisit(visit);
         VisitDto visitDto = visitMapper.toVisitDto(visit);
         headers.setLocation(UriComponentsBuilder.newInstance().path("/api/visits/{id}")
-            .buildAndExpand(visit.getId()).toUri());
+                .buildAndExpand(visit.getId()).toUri());
         return new ResponseEntity<>(visitDto, headers, HttpStatus.CREATED);
     }
 
-
     @PreAuthorize("hasRole(@roles.OWNER_ADMIN)")
     @Override
     public ResponseEntity<PetDto> getOwnersPet(Integer ownerId, Integer petId) {
diff --git a/src/test/java/org/springframework/samples/petclinic/rest/controller/OwnerRestControllerTests.java b/src/test/java/org/springframework/samples/petclinic/rest/controller/OwnerRestControllerTests.java
index 05d7c3244..69a56a71d 100644
--- a/src/test/java/org/springframework/samples/petclinic/rest/controller/OwnerRestControllerTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/rest/controller/OwnerRestControllerTests.java
@@ -26,6 +26,7 @@
 import org.springframework.samples.petclinic.mapper.PetMapper;
 import org.springframework.samples.petclinic.mapper.VisitMapper;
 import org.springframework.samples.petclinic.model.Owner;
+import org.springframework.samples.petclinic.model.Pet;
 import org.springframework.samples.petclinic.rest.advice.ExceptionControllerAdvice;
 import org.springframework.samples.petclinic.rest.dto.OwnerDto;
 import org.springframework.samples.petclinic.rest.dto.PetDto;
@@ -47,7 +48,9 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.never;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
 import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
 
@@ -368,6 +371,26 @@ void testCreatePetError() throws Exception {
             .andExpect(status().isBadRequest()).andDo(MockMvcResultHandlers.print());
     }
 
+    @Test
+    @WithMockUser(roles = "OWNER_ADMIN")
+    void testCreatePetOwnerNotFound() throws Exception {
+        PetDto newPet = pets.get(0);
+        newPet.setId(null);
+        ObjectMapper mapper = JsonMapper.builder()
+           .defaultDateFormat(new SimpleDateFormat("dd/MM/yyyy"))
+           .build();
+
+        String newPetAsJSON = mapper.writeValueAsString(newPet);
+        given(this.clinicService.findOwnerById(999)).willReturn(null);
+
+        this.mockMvc.perform(post("/api/owners/999/pets")
+           .content(newPetAsJSON)
+           .accept(MediaType.APPLICATION_JSON_VALUE)
+           .contentType(MediaType.APPLICATION_JSON_VALUE))
+           .andExpect(status().isNotFound())
+           .andDo(MockMvcResultHandlers.print());
+    }
+
     @Test
     @WithMockUser(roles = "OWNER_ADMIN")
     void testCreateVisitSuccess() throws Exception {