My Cisco ASA wont establish ssl handshake with proxmox server

[chemch]

I have a cisco asa hosting a clientless ssl vpn but the asa can't establish an ssl connection to proxmox server. Please help

 

[TodorPetkov]

Is ASA with the latest firmware? What's the PVE version?
Proxmox is using modern ciphers for the web UI and my experience with ASA shows they lag behind on this. You can run packet capture on the PVE server and inspect it with ssldump/wireshark to see the exchanged TLS communication in terms of TLS version(s), ciphers, etc.

 

[chemch]

The ASA version is 9.8 and the PVE version is 6.3. In chrome the required JS files load, however, the following error is thrown:

HTTP/1.1 501 no such file '/PVE/StdWorkspace.js'
Set-Cookie: webvpn_state=51; path=/; secure
Date: Mon, 26 Apr 2021 03:33:19 GMT
Cache-Control: max-age=0
Pragma: no-cache
Expires: Mon, 26 Apr 2021 03:33:19 GMT
Transfer-Encoding: chunked

Everything else seems to load fine.