diff --git a/api/src/user/services/invitation.service.ts b/api/src/user/services/invitation.service.ts
index f4da2282..69a1cc75 100644
--- a/api/src/user/services/invitation.service.ts
+++ b/api/src/user/services/invitation.service.ts
@@ -39,10 +39,10 @@ export class InvitationService extends BaseService<
     @Inject(InvitationRepository)
     readonly repository: InvitationRepository,
     @Inject(JwtService) private readonly jwtService: JwtService,
-    @Optional() private readonly mailerService: MailerService | undefined,
     private logger: LoggerService,
     protected readonly i18n: I18nService,
     public readonly languageService: LanguageService,
+    @Optional() private readonly mailerService?: MailerService,
   ) {
     super(repository);
   }
diff --git a/api/src/user/services/passwordReset.service.ts b/api/src/user/services/passwordReset.service.ts
index 704e1a9b..8c5d7991 100644
--- a/api/src/user/services/passwordReset.service.ts
+++ b/api/src/user/services/passwordReset.service.ts
@@ -32,11 +32,11 @@ import { UserService } from './user.service';
 export class PasswordResetService {
   constructor(
     @Inject(JwtService) private readonly jwtService: JwtService,
-    @Optional() private readonly mailerService: MailerService | undefined,
     private logger: LoggerService,
     private readonly userService: UserService,
     public readonly i18n: I18nService,
     public readonly languageService: LanguageService,
+    @Optional() private readonly mailerService: MailerService,
   ) {}
 
   public readonly jwtSignOptions: JwtSignOptions = {
@@ -105,7 +105,7 @@ export class PasswordResetService {
     // first step is to check if the token has been used
     const user = await this.userService.findOne({ email: payload.email });
 
-    if (!user.resetToken || compareSync(user.resetToken, token)) {
+    if (!user?.resetToken || compareSync(user.resetToken, token)) {
       throw new UnauthorizedException('Invalid token');
     }
 
diff --git a/api/src/user/services/validate-account.service.ts b/api/src/user/services/validate-account.service.ts
index c7a7d203..6872ed2e 100644
--- a/api/src/user/services/validate-account.service.ts
+++ b/api/src/user/services/validate-account.service.ts
@@ -36,10 +36,10 @@ export class ValidateAccountService {
   constructor(
     @Inject(JwtService) private readonly jwtService: JwtService,
     private readonly userService: UserService,
-    @Optional() private readonly mailerService: MailerService | undefined,
     private logger: LoggerService,
     private readonly i18n: I18nService,
     private readonly languageService: LanguageService,
+    @Optional() private readonly mailerService?: MailerService,
   ) {}
 
   /**