Update app.py

app.py

@@ -540,7 +540,7 @@ def issue_tokens(send,rec,amount):
                         balance = 0
                     balance_rec =int(balance)+int(amount)
 
-                if balance < 0:
+                if balance_send < 0:
                     mes ="Not enough tokens"
                     p = False
         if z==False: