The error (Unable to Create TNT Label Error: 3005 Sender address: address line 1 has exceeded its maximum length) from TNT occurs when the warehouse address exceeds the character limit of thirty-five for Address Line 1.
To resolve this, review the address by following these steps:
Click Warehouse then Manage Warehouses.
Find the warehouse.
Click Edit.
Ensure the address fits within the 35-character limit for Address Line 1, 2 and 3.