Getting error when trying to update Cisco Embedded Wireless Controller

[Josizzle]

I'm trying to update the software on my Cisco Embedded Wireless Controller on Catalyst Access Points Version 17.12.4 via Web UI. I entered my CCO credentials, ran a software check and clicked save and download. It fails on the WLC Image Download and I get the following error (see below). I've re-entered my credentials and confirmed the username and password is correct but it is still failing. Any assistance or recommendations will be greatly appreciated. Attaching screenshot. 

Cisco Catalyst 9100AX series (2)
Product No. C9105AXI-B

HTTP 503 Error: upstream connect error or disconnect/reset before headers. reset reason: connection termination Please check your username/password and try again

Install Logs
install_add: START Sat Nov 22 01:19:03 UTC 2025
Downloading file cco://******/image-name/C9800-AP-iosxe-wlc.bin/version/17.12.6a/download_path/backup_image/
FAILED: Failed to download file cco://******/image-name/C9800-AP-iosxe-wlc.bin/version/17.12.6a/download_path/backup_image/: Incorrect Login/Password

[Mark Elsen · Accepted solution]

  - @Josizzle            Download the EWC software first to a local repository and install from there;
                                that will also verify if the given credentials are correct 

  M.

[Josizzle]

Thanks @Mark Elsen . I was able to download the files locally on my server and upgrade the AP and controller image from there. I ran the following steps so now I have it documented for future use. Glad to know there are people out in the Cisco community looking to help IT guys like myself. 

Steps 

• Run Software Check 
• Download EWC software locally to server 
• Select Desktop (HTTP) mode 
• Upload controller image (see screenshot) 
• Upload AP image (see screenshot) 
• Click Save and Download (upgrade process begins...) 
• Activate new software when software upgrade status appears on Activate 
• Network reload triggered (wait for AP devices to reboot and reload) 
• Validate Wi-Fi works after update complete (Upgrade Complete) 
• Backup configuration (if needed) 

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