diff --git a/komga/src/main/kotlin/org/gotson/komga/domain/model/KomgaUser.kt b/komga/src/main/kotlin/org/gotson/komga/domain/model/KomgaUser.kt
index 1861536a4..0a29d2bd8 100644
--- a/komga/src/main/kotlin/org/gotson/komga/domain/model/KomgaUser.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/domain/model/KomgaUser.kt
@@ -11,7 +11,7 @@ const val ROLE_FILE_DOWNLOAD = "FILE_DOWNLOAD"
 const val ROLE_PAGE_STREAMING = "PAGE_STREAMING"
 
 data class KomgaUser(
-  @Email
+  @Email(regexp = ".+@.+\\..+")
   @NotBlank
   val email: String,
   @NotBlank
diff --git a/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/ClaimController.kt b/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/ClaimController.kt
index 1383f0627..132ac95f4 100644
--- a/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/ClaimController.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/ClaimController.kt
@@ -28,7 +28,7 @@ class ClaimController(
 
   @PostMapping
   fun claimAdmin(
-    @Email @RequestHeader("X-Komga-Email") email: String,
+    @Email(regexp = ".+@.+\\..+") @RequestHeader("X-Komga-Email") email: String,
     @NotBlank @RequestHeader("X-Komga-Password") password: String
   ): UserDto {
     if (userDetailsLifecycle.countUsers() > 0)
diff --git a/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/ErrorHandlingControllerAdvice.kt b/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/ErrorHandlingControllerAdvice.kt
new file mode 100644
index 000000000..9a8201e93
--- /dev/null
+++ b/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/ErrorHandlingControllerAdvice.kt
@@ -0,0 +1,41 @@
+package org.gotson.komga.interfaces.rest
+
+import org.springframework.http.HttpStatus
+import org.springframework.web.bind.MethodArgumentNotValidException
+import org.springframework.web.bind.annotation.ControllerAdvice
+import org.springframework.web.bind.annotation.ExceptionHandler
+import org.springframework.web.bind.annotation.ResponseBody
+import org.springframework.web.bind.annotation.ResponseStatus
+import javax.validation.ConstraintViolationException
+
+@ControllerAdvice
+class ErrorHandlingControllerAdvice {
+  @ExceptionHandler(ConstraintViolationException::class)
+  @ResponseStatus(HttpStatus.BAD_REQUEST)
+  @ResponseBody
+  fun onConstraintValidationException(
+    e: ConstraintViolationException
+  ): ValidationErrorResponse =
+    ValidationErrorResponse(
+      e.constraintViolations.map { Violation(it.propertyPath.toString(), it.message) }
+    )
+
+  @ExceptionHandler(MethodArgumentNotValidException::class)
+  @ResponseStatus(HttpStatus.BAD_REQUEST)
+  @ResponseBody
+  fun onMethodArgumentNotValidException(
+    e: MethodArgumentNotValidException
+  ): ValidationErrorResponse =
+    ValidationErrorResponse(
+      e.bindingResult.fieldErrors.map { Violation(it.field, it.defaultMessage) }
+    )
+}
+
+data class ValidationErrorResponse(
+  val violations: List<Violation> = emptyList()
+)
+
+data class Violation(
+  val fieldName: String? = null,
+  val message: String? = null
+)
diff --git a/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/dto/UserDto.kt b/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/dto/UserDto.kt
index 44759904b..88f9e1737 100644
--- a/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/dto/UserDto.kt
+++ b/komga/src/main/kotlin/org/gotson/komga/interfaces/rest/dto/UserDto.kt
@@ -45,7 +45,7 @@ fun KomgaUser.toWithSharedLibrariesDto() =
   )
 
 data class UserCreationDto(
-  @get:Email val email: String,
+  @get:Email(regexp = ".+@.+\\..+") val email: String,
   @get:NotBlank val password: String,
   val roles: List<String> = emptyList()
 ) {
diff --git a/komga/src/test/kotlin/org/gotson/komga/interfaces/rest/ClaimControllerTest.kt b/komga/src/test/kotlin/org/gotson/komga/interfaces/rest/ClaimControllerTest.kt
new file mode 100644
index 000000000..367581580
--- /dev/null
+++ b/komga/src/test/kotlin/org/gotson/komga/interfaces/rest/ClaimControllerTest.kt
@@ -0,0 +1,34 @@
+package org.gotson.komga.interfaces.rest
+
+import org.junit.jupiter.api.extension.ExtendWith
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
+import org.springframework.beans.factory.annotation.Autowired
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc
+import org.springframework.boot.test.context.SpringBootTest
+import org.springframework.test.context.ActiveProfiles
+import org.springframework.test.context.junit.jupiter.SpringExtension
+import org.springframework.test.web.servlet.MockMvc
+import org.springframework.test.web.servlet.post
+
+@ExtendWith(SpringExtension::class)
+@SpringBootTest
+@AutoConfigureMockMvc(printOnlyOnFailure = false)
+@ActiveProfiles("test")
+class ClaimControllerTest(
+  @Autowired private val mockMvc: MockMvc
+
+) {
+  @ParameterizedTest
+  @ValueSource(strings = ["user", "user@domain"])
+  fun `given unclaimed server when claiming with invalid email address then returns bad request`(email: String) {
+    val password = "password"
+
+    mockMvc.post("/api/v1/claim") {
+      header("X-Komga-Email", email)
+      header("X-Komga-Password", password)
+    }.andExpect {
+      status { isBadRequest() }
+    }
+  }
+}
diff --git a/komga/src/test/kotlin/org/gotson/komga/interfaces/rest/UserControllerTest.kt b/komga/src/test/kotlin/org/gotson/komga/interfaces/rest/UserControllerTest.kt
index c19d03262..e50a0dfc5 100644
--- a/komga/src/test/kotlin/org/gotson/komga/interfaces/rest/UserControllerTest.kt
+++ b/komga/src/test/kotlin/org/gotson/komga/interfaces/rest/UserControllerTest.kt
@@ -1,7 +1,9 @@
 package org.gotson.komga.interfaces.rest
 
-import org.junit.jupiter.api.Test
+import org.gotson.komga.domain.model.ROLE_ADMIN
 import org.junit.jupiter.api.extension.ExtendWith
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.ValueSource
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc
 import org.springframework.boot.test.context.SpringBootTest
@@ -9,26 +11,27 @@ import org.springframework.http.MediaType
 import org.springframework.test.context.ActiveProfiles
 import org.springframework.test.context.junit.jupiter.SpringExtension
 import org.springframework.test.web.servlet.MockMvc
-import org.springframework.test.web.servlet.patch
+import org.springframework.test.web.servlet.post
 
 @ExtendWith(SpringExtension::class)
 @SpringBootTest
 @AutoConfigureMockMvc(printOnlyOnFailure = false)
-@ActiveProfiles("demo", "test")
+@ActiveProfiles("test")
 class UserControllerTest(
   @Autowired private val mockMvc: MockMvc
 
 ) {
-  @Test
-  @WithMockCustomUser
-  fun `given demo profile is active when a user tries to update its password via api then returns forbidden`() {
-    val jsonString = """{"password":"new"}"""
+  @ParameterizedTest
+  @ValueSource(strings = ["user", "user@domain"])
+  @WithMockCustomUser(roles = [ROLE_ADMIN])
+  fun `when creating a user with invalid email then returns bad request`(email: String) {
+    val jsonString = """{"email":"$email","password":"password"}"""
 
-    mockMvc.patch("/api/v1/users/me/password") {
+    mockMvc.post("/api/v1/users") {
       contentType = MediaType.APPLICATION_JSON
       content = jsonString
     }.andExpect {
-      status { isForbidden() }
+      status { isBadRequest() }
     }
   }
 }