Error: object of type 'NoneType' has no len() when clicking Find in Download Products

[gang-liuyi]

Description: I encountered an error when attempting to search for Sentinel-2 products using the Download Products tool. The error occurs immediately upon clicking the "Find" button.

Steps to Reproduce:

I am trying to download satellite imagery using the Semi-Automatic Classification Plugin (SCP) in QGIS. Here is the workflow I followed:

1. I went to the SCP menu -> Download products.
2. In the Login data tab, I entered my Copernicus Data Space Ecosystem username and password and checked the 'remember' box.
3. In the Search tab, I clicked 'Add OpenStreetMap to the map' to use it as a base layer.
4. I set the search area (UL and LR) by clicking on the map.
5. I selected Sentinel-2 as the product.
6. I set the date range from 2025-02-01 to 2026-02-01, Max cloud cover to 50%, and Results to 5.
7. I clicked the 'Find' (magnifying glass) button, the error object of type 'NoneType' has no len() appeared immediately. It seems the plugin crashes before even attempting to start the download.

Environment:
OS: Windows 11
QGIS Version: 3.40.14-LTR
Plugin Version: 8.5.0