If you receive this error when booking your consignments, this would usually indicate that your UPS Shipping credentials have been changed.
To resolve this, you will need to reconnect Shiptheory to your UPS account by adding a new carrier integration of UPS. This can be achieved by following the UPS connection guide below.
UPS Shipping Connection Guide: https://support.shiptheory.com/en/support/solutions/articles/24000086950-how-to-connect-your-ups-shipping-account-with-shiptheory
If you continue to have issues, please feel free to contact our Support Team on email via email at "support@shiptheory.com" or on 0117 403 4313.