VPN Mobile Client connection to re-imaged 80.20 firewall failed

[Kevin_Taylor]

Management station version 80.20.  Re-imaged 77:30 firewall with 80.20 using ISOMorphic.  Attempted connection using version 80.30 of the CP Mobile VPN client.  Timed out after getting to 47%.  Last detailed message on VPN client - User Username authenticated by Firewall authentication.  Using Legacy Authentication -Queries Domain Controller for credentials.  Third party looked at setting and were determined to be correct. Looked at all logs and could not identify issue  Re-imaged with 80.10 using ISOMorphic same failure, I then re-imaged using ISOMorphic to 77:30 and it worked.  

I've actually re-imaged a 77:30 to 80:20 using ISOMorphic on a different firewall and got the VPN client to connected.

I don't recall seeing the Certificate/Fingerprint prompt to Trust when connecting to 80.20/10.  I had connected to this firewall before the upgrade, but I believe I should have received the prompt to Trust when it was version 80.20/10.

Is it plausible this is what caused connectivity to fail?