This error appears when the shipping label is not fetched from marketplace or integrated carrier with Wareo even after multiple requests. This may be during high pick operation which leads to slowness in API or wrong carrier configurations.
Action required from your end
1. Refetch shipping label: Click on the Fetch Document button under the missing label tab of packing state.
2. Ensure correct carrier settings: To check carrier setting navigate to Warehouse Setup > Carrier Module.
We hope the details above were helpful for you. Please feel free to share with us if require further assistance and will be happy to take it up.