This specific bug causes the ISSU Compatibility Matrix ( comp_matrix.xml ) to fail with the NCSW10301 error even if the image itself downloads.
Download the required software image manually to your laptop or a local server from the Cisco Software Central . This specific bug causes the ISSU Compatibility Matrix
Corporate proxies or next-gen firewalls sometimes scan or modify HTTPS traffic. If the proxy injects content or alters headers, the cryptographic integrity of the metadata (including the trans-id) breaks. This specific bug causes the ISSU Compatibility Matrix