diff --git a/www/web/warppay/models.py b/www/web/warppay/models.py
index 4d3a099a5f5d09f5ae91d79d882cd0440923af3a..a009742b8fe5b37ae1a9929bf8ff58aa96e7c428 100644
--- a/www/web/warppay/models.py
+++ b/www/web/warppay/models.py
@@ -54,7 +54,7 @@ class TransactionLog(models.Model):
 
 class UserCredit(models.Model):
     uid = models.CharField(max_length=100,unique=True)
-    card_id = models.CharField(null=True, blank=True) # Unique only with django 1.11
+    card_id = models.CharField(max_length=255, null=True, blank=True) # Unique only with django 1.11
     credit = models.FloatField()
     pinCode = models.CharField(max_length=100, blank=True, null=True)