When creating DHL shipments (labels) this error occurs:
too many requests
The sandbox mode is enabled in the module configuration in Magento. In this mode, hard-coded login data for the DHL gateway will be used.
If too many module users are testing the module at the same time, the above problem can occur, because all tests go to the same account at DHL. The test login data are shared by all users of the DHL module.
Try again after 1 hour.
Change from sandbox to production mode. Then your personal login data will be used, which prevents the above problem.
When changing to production mode, you must configure your personal login data and your customer number (EKP) together with the participation numbers.