diff --git a/apps/authorization/serializers/common.py b/apps/authorization/serializers/common.py
index 13121f78..d99a2dc2 100644
--- a/apps/authorization/serializers/common.py
+++ b/apps/authorization/serializers/common.py
@@ -38,13 +38,13 @@ class SignupSerializer(serializers.ModelSerializer):
         valid = utils_methods.username_validator(username=value)
         if not valid:
             raise utils_exceptions.NotValidUsernameError()
-        if account_models.User.objects.filter(username__icontains=value).exists():
+        if account_models.User.objects.filter(username__ilike=value).exists():
             raise serializers.ValidationError()
         return value
 
     def validate_email(self, value):
         """Validate email"""
-        if account_models.User.objects.filter(email__icontains=value).exists():
+        if account_models.User.objects.filter(email__ilike=value).exists():
             raise serializers.ValidationError()
         return value