diff --git a/trading_assistant_api/services/user/Dockerfile b/trading_assistant_api/services/user/Dockerfile
index 6fce193..56557e8 100644
--- a/trading_assistant_api/services/user/Dockerfile
+++ b/trading_assistant_api/services/user/Dockerfile
@@ -1,5 +1,3 @@
-# syntax=docker/dockerfile:1
-
 FROM golang:1.25.7-alpine3.23 AS builder
 WORKDIR /workspace
 RUN apk add --no-cache git
diff --git a/trading_assistant_api/services/user/internal/service/user_service.go b/trading_assistant_api/services/user/internal/service/user_service.go
index ddf8617..3115f0b 100644
--- a/trading_assistant_api/services/user/internal/service/user_service.go
+++ b/trading_assistant_api/services/user/internal/service/user_service.go
@@ -1,11 +1,10 @@
 package service
 
 import (
-	"database/sql"
 	"errors"
+	"strings"
 
 	"common/auth"
-	"github.com/jackc/pgconn"
 	"golang.org/x/crypto/bcrypt"
 	"user/internal/repository"
 )
@@ -93,9 +92,9 @@ func validPassword(p string) bool {
 }
 
 func isUniqueViolation(err error) bool {
-	var pe *pgconn.PgError
-	if errors.As(err, &pe) {
-		return pe.Code == "23505"
+	if err == nil {
+		return false
 	}
-	return false
+	s := err.Error()
+	return strings.Contains(s, "duplicate key") || strings.Contains(s, "unique constraint") || strings.Contains(s, "23505")
 }