When processing FedEx orders, you might come across the "Operation returned an invalid status codeBadRequest' {"status":"error","error_code":"errors.invalid_input","error_message":"Invalid input. The maximum length of 'label_text1' is 20 for this service (158)"} " error.
This error happens when the one or more Label References exceeds the length of 20 characters when using FedEx.
To solve this, you can either:
a) Use shorter Customer Order numbers
b) If that's not possible, or if you're using Fixed References, remove or replace the reference on the Billing Account profile you're processing through as this article indicates: https://support.techdinamics.com/solution/articles/227983-adding-reference-numbers-on-labels-step-by-step-guide-